love and hate collide

you get in a relationship. At first, it's bliss. Eureka! You feel ecstatic even without drugs. For a time, you just cherish what you have. But then something happens, one of you has been bad. The offended party usually gets all the sympathy. But this time it's not you.

You are now on the hot seat. You've been bad. Whether it's through something you did - saying things that hurt, cheated on your partner, lied, manipulated to get something you want, worst, physically hit your partner, or, through something you didn't deliberately do but should have done - omitting to tell the truth when you should have (same as lying), being obtuse, withholding something (again to manipulate), (and everything else that would make one hate you enough to call you a goddamn bitch or bastard or feel like making you disappear on the face of the earth)

If you want to preserve what you have or if you really love your partner, what do you do if you've been bad?