Guilty about a dream (this is long)

For the record, we weren't really a couple, we mostly just hooked up several times and hung out with this group of people. Anyway, we stopped talking years ago, we're not even Facebook friends. No hard feelings or anything just our business with each other was done. 

Fast forward to now. My SO knew him through work before we got together. This other guy moved on before my SO and I met or started talking. ANYWAY ANYWAY, I just feel so guilty about this dream, but my SO doesn't exactly know we were hooking up, just that we hung out. I'm sure he could deduce that we were having sex, but it's never been discussed and he's never asked about it. 

There was nothing that sparked my memory to think of him, I haven't thought of this guy or that group of friends in months, so this dream just came out of nowhere. It bothers me a lot that the dream was so sexy that I was half asleep and even considered getting my vibrator out! I didn't, but I have felt so guilty all day long. If it was a dream about a celebrity or something I definitely wouldn't feel like this, but because it was about this other guy I just feel so horrible! I don't know how to stop feeling so crappy about it! Any advice?