Why Do I Do This?!!

I slept with my old cutbuddy just yesterday. I dont know but i still love him even knowing he doesnt care for me that way...and whats worse is im going to see my bf tomorrow....even though he's p****** me off talking bout sum other b**** that i hate....
But I really dont get why I cant get away from my cutbuddy! Ugh! I have a guy that, even though hes getting on my nerves, I know he really loves me and cares. But a part of me just cant let the other go..But I got to eventually...and maybe I shoudl try now?? Ugh! I feel like crap!! I gotta tell my bf...