I think part of the reason I stopped being Polyfuckamores is the fact that I'm picky. It takes me a long time to get to know people and I'm not really sexually charged until I do. Plus, I really love the cat and mouse games. Hard to do with passer bys, simple encounter and "closed off" people.
Mabey its an age thing but I just find more fun in sleeping with people who I really like and know well. It doesn't stop me from enjoying spontaneic sexually charged encounter (bd/sm/cuddling/kissing kind of stuff) but fucking takes more energy, and I'm picky now.
fucko