Love, the kind you clean up with a mop and bucket

I have a bit of a conundrum right now that's bugging the hell outta me. I've got the opportunity to join in a threesome with a couple of cool people. The problem is, the gal just doesn't seem that into it. Or maybe she's just not into me that way. It wouldn't piss me off if she said, "It was his idea and I'm not interested in being anything but a friend w/o benefits with ya." Either way, there's a distinct lack of enthusiasm there.

I'm one of those silly guys that can't fuck a gal that isn't into it. If she lies there like a dead fish, not interested. If she has to be talked into screwing me, not interested. If she demands that I give her (object) before she'll do anything, Not Interested. I'm funny that way. Yet another reason I don't get laid as much as I'd like.

The other thing that bugs me (since my brain never shuts up like it should), is that if she's not into it and the guy isn't into men (he's not, as far as I know), then why was I asked to join in? My ego is damaged enough from the normal wear and tear in my life, but the thought of pity sex takes things to a whole different level. I don't think I could handle accepting pity. Maybe I have a little self esteem left that says, "You're too good to sell yourself short." Maybe I'm just stubborn. I could be a complete fool, too.

I think too much. What do you think about all of this?