I gotta agree. This guy sees you as pretty much just a living sex toy.
Now, if all you are after is the sex and you are happy with it, then that's fine. But if you want anything more (and from the sounds of it you do; how else could he keep you coming back), then you are indeed being manipulated and I'd even say abused.
I think that you should get out.
I'm an expert at sexual innuendo. I could keep it up all night.