Relationships are give and take.
While I agree with those who say "Matt won't change," I also have to realize that when we broke up, I didn't have a problem with him as much as I did with the lack of commitment.
What Matt did was wrong. I was right to get mad. When I realized this, I approached him (not angrily just to talk to him) and mentioned how I felt. He agreed with me and apologized to me. He told me he was drunk and he became an asshole because his first concern was getting his professors to like him and want him around. The more he drank, the more he pretended his phone wasn't ringing.
I accepted this and forgave him for two reasons.
One, he did admit and apologize for his actions.
Two, If you read below, two nights before this night I behaved badly because of hormones and alcohol. I wanted him to forgive me for what I did, and he did, I would be a very big hypocrite if I ignored my equivalent behavior and pretended his was worse. Also, he didn't even mention the fact that I had behaved badly two days prior to this, and accepted everything he did without saying "Well, you did this!" to me.
Last night on my birthday night, he was amazing.
This is my second birthday with him, the first one we had only been dating a month and a half before it and he didn't really do much for the date.
This one he went out of his way to do exactly what I wanted. I didn't even ask him to do all that he did last night. After the bars got old, he invited me and all my friends back to his place saying "Well, I don't want you to have them to your house because then you'll have to clean up after them, and that's not fair to you."

We did have one argument last night.
He brought up GH, and how quickly I had moved on from him.
He was drunk and I was drunk.
I just left the room, stating that I had defended myself enough on this subject.
He followed me and apologized and then told me he was just concerned that I wasn't in this relationship as much as he was.
I started laughing.
I told him that I didn't leave the relationship because of GH, I left it because "I was concerned that he wasn't in this relationship as much as I was."
He and I laid down, and I curled to him with my face in his neck, and while he stroked my hair he told me that he was leaving Indiana in a year but he planned on taking me with him. He told me that he wouldn't find anyone as perfect as me and he was sorry he was a dick sometimes to me. I apologized for being a bitch to him sometimes, and we both fell asleep in a drunken haze of happiness.