Ok, So Everything Is Good... And Now My Ex Is Back

Ok, so my relationship has been pretty good for the past few weeks. A sparing argument now and then, a pretty rough one two weeks ago, but that was solved. However, now my ex, who ended our relationship on good terms, is back. Well, not back, but she recently contacted me. Anyway, we had made the promise when we broke up that if we didn't have anyone at the end of college, we would try to get back together. However, I remember very well that our relationship (me and my ex), was a lot better than my current. The only problem is that I'm not sure if my ex would accept me the way my current girlfriend does.
So, the positive side of my ex is I know she will treat me the way I want to be treated. The positive side of my current relationship is that my girlfriend accepts me for all that I am. I think my ex might have some problems with things, but most things would still be ok between us.
My girlfriend asked me the other day "you aren't going to leave me because she's back, are you?" I said no, but I think about the two relationships and try to weigh things. What's more important? Being treated right, or being loved for everything? I'm sure my ex and I would be able to talk over things, but I don't know what to do. Just thinking about it today, I actually thought that going back to my ex might be better for me.