It’s been said a thousand times, trumpeted from every advice column and TV show. Yet I still find clients wondering why their partners don’t change. Somehow they believe the magic of a romantic relationship will free their boy/girlfriend from destructive behavior.

It won’t. If anything, by remaining in a relationship with someone who displays inappropriate behavior you only encourage them to continue.

The behavior doesn’t even have to be inappropriate. A recent client complained to me about her boyfriend who is terrible at planning. She never knows if/when they will see each other. This activates her abandonment issues from her childhood. She tried again and again to explain her abandonment issues to her boyfriend and asked him again and again to be more considerate of her feelings and be more planful.

Ideally, this man would learn to plan like most adults with busy lives and make conscious room in his life for the woman he professes love for. But he’s not going to change because of her abandonment issues. She has two choices, continue with the relationship and work on her issues, knowing that for the rest of their lives he will never be thoughtful around planning. Or end the relationship.

Destructive behavior like drug abuse and violent anger are never ones you should try to change. These types of situations are best left as quickly and safely as possible.

But other behavior—poor housekeeping habits, bad diet, enmeshed relations with family, always being late—these can sometimes be tolerated.

If you find yourself in this type of situation with your partner, look at why the change you are asking for is important to you. Does it say more about you than it does about the other person? What does your partner tolerate in you?

Asking, cajoling, begging and threatening do not work. People change behavior when they feel motivated internally. No amount of external push will get someone to alter their behavior. Accept a person for who he/she is or get out.

Hardly a new idea, but one worth repeating.