I'm having trouble with a guy. Can anyone help me?

I've been on/off talking to this guy since about last May. Around August, we began to date and everything was just dandy. We ended it in October, however, I don't really remember why. But anyhow, on Halloween night we started to talk again and I ended up really, really liking him more than ever. I lost my virginity to him in November, which may or may not have been a mistake (I'm not in any way, shape, or form a slut and wanted to hold onto it until I was older) I'm of decent age, just in case you were wondering. Anyway. In the beginning of January, we got into a big argument and stopped talking for about two days. During these two days, he had with this slutty girl I go to school with, who resembles a diseased cow. We stopped talking since then but recently he's been trying to talk to me non-stop, telling me how sorry he is and that he loves me and didn't realize what he lost at the time. I still have feelings for him, but I can't help but think he's going to hurt me and get with another girl again. He promises me that he won't. I'm not sure what I should do. Should I give him one more chance or get rid of him for good?