TL;dr: I got a blowjob while my friend watched, and I had an opportunity to have my first and only threesome of my life, and I passed it up.

This confession is from my very short first marriage This occurred several months into my marriage that lasted less than a year. I think of it from time to time because it gave me an opportunity to experiment in two areas that I will never be able to experiment with for as long as I am married to my current wife. And at the time it happened, I passed on the opportunity, and I regret to this day not taking better advantage of it.

My ex-wife was not very sexually adventurous, and at the time I really wasn't either. She was pretty close-minded, and we weren't having enough sex anyway so there was no point to ever discuss threesomes or bisexuality together. But we had one of our friends over one night and we were drinking, and somehow I ended up getting a blowjob while our friend watched (let's call him Brian), with a restricted view. He could see my upper body and her head movement, but couldn't see the front of her face or my cock. Basically, I was turned slightly away from him and was blocking my dick with a piece of clothing. My wife was focused on the task at hand and seemed to be into it, of course I was enjoying myself, and Brian seemed interested. I wasn't sure what to take of it at the time, but looking back now, I could have easily fulfilled my fantasy of an MMF threesome with a simple come hither motion towards Brian. At the time, I wasn't really bi-curious, and my desires for threesomes were two women worshiping me. I don't know how my wife would have taken me inviting him in without communication, but I later had doubts that they were doing something behind my back and since we got divorced, who cares about the repercussions anyway. However, now I regret not taking the opportunity. It didn't have to be a sexy bisexual threesome, but certainly Brian and I could have both been included with my then-wife.

After I came, my ex-wife gave me a kiss and went to bed (We lived in a small apartment, so it was the next room over from the living room). Brian and I continued to drink for a while. I think we played a board game, and I don't remember how it came up or what our intentions were, but at some point we were rolling the dice for scenarios that included him and I doing stuff to each other, watching my wife and I do more things, or being able to do things to her. I recall there being a discussion of him and I doing 69, which turned me on, but with my wife in the house it wasn't going to be possible and she didn't really leave very much since she didn't work. Apparently we were being kind of loud about it, because the next morning she was angry because she heard us talking about sucking each other off. I never really told her that it interested me quite a bit, and I have never really talked about this since. But to this day, this is one of the exciting things I've done sexually in my life, but also one of the few (but possibly the biggest) sexual regrets I have in my life.