Old feelings die hard...

I was scrolling through Facebook today and saw that the abusive ex is in a new relationship. And for a second my stomach felt like it was being twisted and yanked right out of my body. The feeling went away very quickly, but it just made me realize what a terrible hold this person still has on me. There is nothing fair about that. Why, after all this time and heartache, does my mind still let me feel that way about such a bad person. Honestly, that moment made me fall even more in love with my current boyfriend. But I just feel like some sort of sadness will always be in the back of my mind, like "if only he could have been a better person." Is there something wrong with me or is this feeling normal for someone who has been through abuse?