I think I'm still s*xually attracted to my ex.

Me (M-20) & my ex (F-21) were in a 1 year relationship. All we did was Hug one time. We broke up. After a year. I have been dating a girl for the last 4 months & we are long distance relationship But whenever I masturbate, right when the dopamine hits, i remember my ex. It feels like I still haven't moved on from my ex. But I did. I love the girl that I'm Dating right now. I don't even know what this is. I hope someone explains & Helps me get out of this. TIA.