I believe I have fallen in love with the wrong man...when I talk to him or see him, I feel like butterflies in my stomach, very much like one felt the first time. If I don't see him or talk to him
I've been in that situation a few times. For me, it never worked out. I think there are some men, straight or not, who also have man-crushes on gay men, but I don't think it goes any further.
I also think that some straight men enjoy feeling attractive, even if that attraction comes from another man. I had that experience once with a male coworker. He's married with a child now. I'm positive he knew about my attraction by statements he made to me.
I have a gay friend who experienced the same with a straight, male, married coworker. His coworker would go out of his way to wear clothing; well fitting, well-worn jeans which left little to the imagination.
Sometimes it's difficult to tell. I hope you find your answer. I know how perplexing and frustrating these situations can be. Sometimes, under the right circumstances, you can just ask.