Originally Posted by lurkette

An apology at this point is irrelevant. It sounds as though things had to get way beyond bad for you to finally see how abusive and unhealthy the relationship was and leave it.

It's difficult to move on when you feel so confused, I know, so now might be a really good time to do some mental/spiritual inventory. Look as clearly as you can (either with a counselor or on your own) at what you can be responsible for in the relationship, whether it's actions you took, things you did or didn't communicate, things you put up with that you didn't want. If you can find the roots of things, great. Look at which of your own behaviors, thoughts, patterns, etc. you want to change. Everything else - the sudden personality shift, the violence - is his and his alone. You are responsible for your reaction to it (staying when you might have gone instead, behaviors that were irresponsible) but not for his behavior.

I wish you the best, and I hope you can look at this as an opportunity to do some real soul-searching and shift the patterns you've carried with you to this point. You're at an age that, in my experience, is a time of change and growth and upheaval for a lot of people. Don't waste the chance to make some real changes in your life; they may feel painful at first but you'll be more yourself for it, if that makes any sense.