If you flirt with your friend's boyfriend, betray a confidence or offer unsolicited advice, for example, your friend may feel you have overstepped your boundaries. Whether or not you meant to do so, an apology can go a long way toward mending the hurt and restoring the relationship, especially if you take the first step. You might also ask what kinds of actions your friend feels are overstepping boundaries so you don't make a similar mistake later.

Discussing the Transgression

Your friend deserves the opportunity to talk to you about your behavior, so alert him that you would like to talk and be willing to listen to his perspective, suggests therapist Mark Tyrrell in the article, "5 Golden Keys to Assertiveness and Setting Boundaries," on his website. Ask him to explain exactly what you did and how it affected him. Accept his feelings as valid and promise not to cross his boundaries again. Promise to be more considerate of his needs in the future.

Define Boundaries

You might have crossed your friends boundaries in other ways, so give her the opportunity to define the boundaries of your friendship, suggests psychologist Irene S. Levine. Be considerate of her needs, such as not monopolizing her time or resources. She can explain what types of behaviors are acceptable in your friendship, such as honoring her other responsibilities or accepting her answer when she tells you she can't do something. Try to make your relationship one where there is an equal exchange of favors and interactions.

Moving Forward

Invite your friend to let you know immediately in a very direct statement if you cross the line again, advises therapist Margarita Tartakovsky in her PsychCentral article, "10 Ways to Build and Preserve Better Boundaries." Also promise to notice if he behaves in a way that shows tension toward you, such as avoiding you, cutting his time with you or not answering your phone calls and texts. Discuss how much you value his friendship and want to respect his feelings and needs.

An Apology and Forgiveness

Fully apologize for overstepping your friend's boundaries, including acknowledging how your actions made your friend feel and your regret for what your actions have done to your relationship, advises psychiatrist Aaron Lazare in his "Psychology Today" article, "Go Ahead, Say You’re Sorry." Ask your friend if there is anything you can do to make amends and then follow through, if you can. Realize that asking for forgiveness and getting it can be two different things, so accept your friend's feelings if she can't forgive you and doesn't want to be your friend. With time, the two of you might resolve the situation, even if it doesn't immediately look like that will occur.