Rules about FWB?

So this past month I been having sex with one of my friend . We hung out one night and had sex and then every since that day we would text eachother and ask to “hangout” . We would have sex at least once every week. But we haven’t had the “talk”. So I don’t know if we’re exclusive or is there any rules. Should i try to talk to him about it? Or just leave it as it be? I don’t wanna scare him away because I really enjoy the sex. And maybe I do have a little bit feelings for him too.... 😣😣