In love with the wrong person

Have you ever fell in love with a whore? Not like a prostitute, but someone who always has multiple partners. If not, you're lucky...if yes, sucks doesn't it? After I broke up with my boyfriend, I hooked up with one of my friends at a party for a rebound, and ever since then we've had kind of a fling. I thought that he would be perfect for an FWB because he's a whore, but I somehow got feelings for him anyway... However, I thought that if I ignored it, we could continue as FWBs because it's fun, but then I got busy with school and my family and haven't talked to him as much. Now, I barely hear from him which is fine, but I still want him...the problem is that he doesn't talk to me, like he's mad at me or doesn't want me anymore...but when he does talk to me, it's nothing like we had while we were "together," it's like he's just my friend again... I know it's for the best, but I still have feelings for him... Now I'm trying to find other people but it's not working, and I just want this pain to go away but nothing's working...what happened, and what should I do?