What is the 3rd Year Relationship Theory on TikTok?

Licensed clinical psychologist Philip Glickman, PsyD, explains why the 3rd year of a relationship tends to be the hardest

Co-authored by Philip Glickman, PsyD and Marcus Pruitt, BS

Last Updated: March 9, 2026 Fact Checked

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What is the 3rd year theory?

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Significance

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Common Problems

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Overcoming Challenges

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Is the theory true?

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It feels like there’s a new theory coming from TikTok every week. There’s the bird theory, the lavender soap theory, the burnt toast theory, and now, the 3rd year relationship theory. The 3rd year relationship theory suggests that your relationship really gets tested in the 3rd year you’re with your partner. But is it true? In this article, we partnered with mental health and relationship experts to help us explain what the 3rd year theory is, why the 3rd year is significant in relationships, common problems during this period (and how to deal with them), and more!

Explaining the 3rd Year Relationship Theory

Licensed clinical psychologist Philip Glickman, PsyD, says the 3rd year relationship theory is the belief that the 3rd year is when couples often face an adjustment period. Cultural, financial, and lifestyle differences start to become more apparent, and if issues can’t be resolved, couples may break up.

Section 1 of 5:

What is the 3rd year theory in relationships?

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The 3rd year relationship theory states that your relationship will be tested in its 3rd year. Dr. Glickman explains, “The 3rd-year relationship theory is the idea that couples often face an adjustment around the three-year mark in their relationship. The first year may be the honeymoon phase, and the second year may become more serious, when couples might move in together. By the third year, marriage or long-term commitment may start to feel like a real possibility, which can add pressure.”^{[1]
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Expert Source

Philip Glickman, PsyD
Licensed Clinical Psychologist

Expert Interview} It’s considered a make-or-break point in a relationship, and if you can grow with your partner and make it through, your relationship can survive practically anything.^{[2]
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- TikTok Example: On February 13, 2026, @limbicemotions posted a video explaining the 3rd year relationship theory, saying that during the 3rd year, love becomes more about patience and communication than a feeling.
- TikTok Example: On April 3, 2025, @avamadeleinee posted a video about 3rd year relationship theory, saying the problems in long-term relationships can boil over and “the length of a relationship does not determine the strength of a relationship.”
- The 3rd year relationship theory is also known as the “three-year itch,” and is characterized by boredom, waning passion, and apparent differences.
Meet the wikiHow Experts

Philip Glickman, PsyD, is a licensed clinical psychologist, the Director of Wellness Road Psychology, and a member of the American Psychological Association.

Nora Oliver is a relationship and certified life coach in Boston, Massachusetts. She specializes in helping others discover who they are and how they want to live their lives.

Elvina Lui, MFT, is a licensed marriage and family therapist specializing in relationship counseling based in the San Francisco Bay Area. She has over 13 years of counseling experience.

Emyli Lovz is a dating and relationship coach for men based in San Francisco, CA. She has 14 years of experience.
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It also relates to the 1s and 3s rule of relationships. Coined by Reddit user u/lalalava in a post in r/OkCupid, the 1s and 3s rule says big relationship decisions happen at the 1st and 3rd date, 1st and 3rd month, 1st and 3rd year, and 10th and 30th years of relationships. It isn’t set in stone, as each relationship is different, but the logic is sound:
- 1st and 3rd Date: The 1st date is when you decide if you want to give them a try. The 3rd date is when you decide if they’re a serious prospect.
- 1st and 3rd Month: The 1st month is when you decide if you want to be exclusive. The 3rd month is when you decide if you’re serious about committing to them.
- 1st and 3rd Year: The 1st year is when you decide if you could have a future together. The 3rd year is when the honeymoon phase wears off, and you decide if you still like each other.
- 10th and 30th Years: The 10th year is when you may have a midlife crisis about being together for the long haul. The 30th year is when the kids are out of the house, and you decide if you’ll happily retire with your partner.

Section 2 of 5:

Why the 3rd Year is Significant in Relationships

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The 3rd year is when differences start to arise, and you heavily consider the future. During the 3rd year of a relationship, the honeymoon phase begins to wear off. “The main idea is that the initial excitement fades and the relationship becomes more routine,” Dr. Glickman says. “It’s not a strict rule, but it’s common for issues like communication problems, differences in expectations, or questions about long-term commitment to surface around this time.”^{[3]
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Expert Source

Philip Glickman, PsyD
Licensed Clinical Psychologist

Expert Interview}
- Political, career, religious, and familial differences may become more apparent, leading you to wonder about the future and whether or not your partner is truly the person you see it with.
- “If these issues can’t be resolved, couples may break up. If they work through them, the relationship can grow stronger and move forward,” according to Dr. Glickman.^{[4]
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  Philip Glickman, PsyD
  Licensed Clinical Psychologist
  
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- If you address these conflicts with grace and understanding, you can go on to have a long-lasting relationship. If they continue to go unaddressed or you just can’t find a common ground, you may find that you’re better off apart.

Section 3 of 5:

Common Problems in the 3rd Year of Relationships

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Financial and lifestyle differences emerge in the 3rd year. By the 3rd year, you’ve gotten to know your partner well, and now you’re starting to wonder how your differences will impact the relationship. This can cause a host of problems to arise as you start to reassess the foundation of your relationship, including:
- Differences of opinion on parenthood and/or parenting styles
- Cultural differences
- Differences of opinion on marriage
- Financial issues
- Career or lifestyle changes
- Differences in political or religious beliefs
- Poor relationship with in-laws
- Poor relationship with your partner’s circle of friends

Section 4 of 5:

How to Overcome the 3rd Year Relationship Theory

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Dedicate time to checking in on each other. Dr. Glickman says that “an ounce of prevention is worth a pound of cure.”^{[5]
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Expert Source

Philip Glickman, PsyD
Licensed Clinical Psychologist

Expert Interview} Taking time to check on your partner, especially after arguments, and asking questions to let them know you still care will help nip any issues in the bud before they turn into resentment.
- This also applies if you’re just beginning the relationship. Take time to get to know your partner so you can understand what makes them tick, then check in when those buttons get pressed.
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Communicate with each other. Communicating with your partner is essential for keeping the relationship alive. “Whether you like what might come out of your partner’s mouth or not, it’s important to be there and listen, and… view whatever is happening from their side, not so much your side,” says relationship coach Nora Oliver.^{[6]
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Nora Oliver
Relationships Coach

Expert Interview}
- This will help you understand where they’re coming from and empathize with what they’re going through, which is crucial for a healthy relationship.
- For example, if you’re struggling at work and a bit less attentive, tell your partner, “I’m sorry for not being present. I’ve been having a hard time at work,” to open the conversation.
- If something is weighing on your relationship, tell your partner what’s going on and why it’s impacting the relationship, using “I” statements so they know you aren’t blaming them.
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Remember, it’s you and them against the problem. It’s easy to get lost in conflict and go for the gut when you’re arguing with your partner, but relationship expert Elvina Lui, MFT, says, “In the face of external pressures, never ever blame or take out frustration on each other. That is the beginning of a fracture that can break the relationship.”^{[7]
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Elvina Lui, MFT
Relationship Expert

Expert Interview} Instead, work with your partner to solve whatever is weighing on you two.
- For example, if one of you is stressed about work, try to create a relaxing environment at home to ease that stress.
- If you two are arguing about lifestyle differences, sit down and try to come to a compromise instead of going back and forth about what you disagree with.
- Conflict is a normal part of a relationship. Dating and relationship coach Emyli Lovz says that “it’s a problem if you have no fights at all,” as it’s a sign that someone isn’t communicating.^{[8]
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- It’s important to address problems as they come up, or they can breed resentment the longer they go unaddressed.
Matchmaker and relationship coach Hoda Abrahim says that “any long-term relationship is going to go through periods of difficulty,” and finding core values that keep you aligned and connected will help hold that connection when you do go through those difficult times.^{[9]
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Hoda Abrahim
Matchmaker and Relationship Coach

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Spend quality time with each other. Licensed mental health counselor Laura Richer says, “You have to intentionally make time for each other, whatever that might look like…relationships really need connection. When you can’t facilitate that, it makes it more and more difficult [to sustain] the relationship.”^{[10]
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Laura Richer
Licensed Mental Health Counselor

Expert Interview}
- Quality time can look like a weekly date night, game night, or movie night. It can also look like spending time together painting, reading, or calling each other while you both cook dinner.
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Remember to take care of yourself, too. In a relationship, it’s important to dedicate time to yourself so you find hobbies and interests outside of your partner and can be happy outside of them. This doesn’t mean you have to ice them out; it just means you have to have personal interests to keep yourself well-rounded and fulfilled. Practice physical, emotional, and educational self-care by doing the following:
- Physical Self-Care: Eat a healthy diet, get exercise, shower, and brush your teeth.
- Emotional Self-Care: Monitor how you feel around others and adjust the time you spend with them accordingly. Set appropriate boundaries when needed.
- Educational Self-Care: Make sure you’re having novel experiences, like reading, learning, and putting yourself in situations where you have to use the information you know.

Section 5 of 5:

Is the 3rd year relationship theory true?

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While it isn’t scientifically studied, the 3rd year relationship theory has been backed by plenty of couples and single people as a period where the relationship’s stability gets tested. The time range may vary depending on how much time you spend with your partner and the level of communication you engage in, but generally, the theory is true.