FWB?!?!

This guy and I have been "hooking up" for a couple (3) months now and we act like we're together w/o the strings attached.
Everything is great but can't seem to shake off the feeling of being 'used' (although I'm enjoying what we have)
Also, he seems to get a bit jealous of what I do and it's kinda cute, kinda annoying
Anyone on the same/similar boat as me?!