Friends with benefits

So me and this boy have been talking on and off for years always pretty much friends he had a gf, recently his broke up with her, we both know there's sooo much sexual cemistry but we've never done anything... Up until the other night. We didn't have sex but done other things, he doesn't want another relationship and I wouldn't want to go out with him because would never trust but I'm scared I'll catch feelings but regular sex would be great? Anyone got any advice how to keep the feelings out!!