It’s pretty cliche to say at this point, but trust really is the foundation of any healthy relationship. Even small lies can destroy it, which ends up creating distance and suspicion. Certain lies are more devastating than others, and those are the ones that carry the potential for long-term damage — and in some cases, ending the relationship completely. While uncomfortable truths are sometimes necessary, these kinds of major lies almost always cause way more harm than the temporary discomfort of being upfront and honest.
1. “I’ve never cheated before.”
Cheating is one of the most devastating betrayals within a relationship, Psychology Today explains. Lying about a past affair, whether a one-time indiscretion or a pattern of behavior, strips your current partner of the right to make informed decisions about the relationship. While admitting a past mistake is difficult, if this previous infidelity has a chance of coming to light, it’s really important to be upfront to avoid even greater fallout down the line.
2. “I don’t want to have kids.” (When you secretly do)
Views on family planning should be discussed openly, especially in committed relationships. Lying about this fundamental desire to deceive someone into staying is a betrayal of their reproductive choices and wastes precious time they could be building the kind of life they want with a like-minded partner.
3. “I love you.” (When you don’t…or aren’t sure yet)
These three words carry immense weight. Saying “I love you” should be meaningful and sincere, not a manipulative tool. It builds false security and deepens emotional investment when feelings aren’t genuine. Be honest about where you’re at emotionally (“I’m not there yet, but I really like you and see potential”) to avoid even greater heartbreak.
4. “It’s just a friend.” (When there are romantic feelings)
Minimizing a connection that treads into emotional affair territory or has the potential to blossom into something physical is a betrayal. Being honest about your feelings or attraction to someone else opens a difficult but necessary conversation, allowing your partner to make informed choices about the boundaries they need to feel secure.
5. “I’m clean.” (When you have an active addiction)
Hiding an addiction, whether to substances or destructive behaviors like compulsive gambling, destroys trust and your partner’s feeling of safety. It’s impossible to have a healthy, supportive relationship without honesty about this struggle. While seeking help requires courage, lying keeps you trapped in a destructive cycle, sabotaging the very relationship that could be a source of strength.
6. “I’m working late.” (When you’re doing anything else)
Chronic lying about your whereabouts, even for seemingly ‘small’ things, erodes trust. It makes your partner doubt your word, leading to insecurity and suspicion. Habitual lying, even if not covering up major betrayals, creates an atmosphere where genuine intimacy is difficult to achieve.
7. “I’m terrible with money, but I have it under control.”
Significant undisclosed debt, reckless spending, or lying about finances directly impacts your partner’s life, especially in cohabiting or married situations. Financial dishonesty can threaten your shared future and place an unfair burden on the more responsible partner. Transparency, even about mistakes, sets the stage for either creating a plan together as a team or making clear choices about your financial compatibility.
8. “I support your career/dreams 100%.” (When you secretly feel threatened)
Jealousy and insecurity can be powerful emotions. If your partner’s success stirs up negative feelings within you, lying and feigning unbridled support undermines them. Seek outside support (therapy, trusted friend) to work through your insecurities rather than subtly sabotaging your partner’s ambitions. A healthy relationship celebrates each other’s wins, not secretly wishes for their failure.
9. Lies about your past that are fundamental to who you are.
Major fabrications about anything from criminal history, past marriages, previous children, or even your real identity create a relationship built on a false foundation. While everyone deserves a chance at redemption, you owe your partner the right to make informed choices about who they’re sharing their life with. If you fear your past will make them leave, a painful upfront conversation is ultimately kinder than a devastating betrayal down the line.
10. “There’s nothing wrong.” (When you’re deeply unhappy)
Faking contentment when you’re miserable in the relationship denies your partner the opportunity to try to address the situation. It leads to building resentment and feeling trapped, which can ultimately lead to destructive behavior or a less-than-amicable ending. Being honest, even when it’s difficult, opens the door for either repairing the connection or realizing it’s time to go your separate ways.
11. “It’s not you, it’s me.” (When it’s really them)
Using this cliché as a way to avoid a difficult conversation is cowardly and ultimately less compassionate. If there are specific behaviors or incompatibilities causing the rift, provide some concrete information that allows for self-awareness and potential growth, even if it means ending the relationship. While a kinder breakup than outright cruelty, it still leaves your partner confused with no opportunity for closure.
12. “I respect your family/friends.” (When you genuinely don’t)
Pretending to like your partner’s loved ones breeds resentment and makes social situations even more awkward. You don’t have to adore them, but respectful interactions are part of a healthy relationship. Honesty about specific struggles is a better approach (“Could we limit time with your brother, his stories trigger my anxiety”) rather than outright faking affection long-term.
13. “Nothing happened, it was just [person’s name].”
Downplaying an emotional connection or minimizing flirtations with an ex or coworker with manipulative phrases like this lays the groundwork for gaslighting your partner when their intuition senses something is off. If it feels wrong, it likely is. Honest communication about how interactions with certain people make you feel is a healthier approach that builds, not destroys, trust.
14. Exaggerating or faking an illness or major crisis.
Craving sympathy or using fabricated drama to manipulate your partner or avoid responsibility is incredibly toxic. It erodes trust and over time, drains your partner’s emotional reserves. This pattern of lying undermines genuine support when you actually do face a real crisis in the future.
15. Lies that weaponize your partner’s vulnerabilities.
Knowing your partner’s deepest fears and insecurities, and deliberately using them as a means of manipulation during arguments is emotional cruelty. It erodes their sense of trust and safety within the relationship. Healthy relationships should be a safe haven, not a battleground where your past pain is used against you.
