Abusers are skilled at manipulation—so much so that they actually convince their partners that their physical or verbal outbursts are the result of misbehavior on your part. The aim is to make you doubt yourself and your self worth as a good person. That's why most victims of abuse continue to excuse or forgive their partner's cruel behavior.
If they own up to what they've done, they'll make excuses for why they did it and "promise" that it will never happen again. They may shower you with gifts to "prove" how much they love you - or how serious they are about changing. You'll want to believe them, but if this is something that's happened before, it's highly unlikely that he/she will really change.
The longer you stay with someone who can manipulate your feelings and emotions, the more you will doubt your own perceptions of reality. You can trust yourself again - with the right kind of help and support!