My ** buddy and my son

This is a little long and a bit fragmented but a very true story. A little back story...I was married for 5 years and about 2 years after my divorce I finally came out as gay. For the past 8 months or so, I have been hooking up with a guy I met online. We are both into the same taboo kind of stuff so we hit it off pretty well.. We both approached the situation as a "No strings" kind of thing. We just wanted to have funding. Anyway, about 3 months aboard, on a Friday night, we were going at it, I was on all 4s, he was behind me. I had turned my head back to kiss him, which I love to do while a guy is ** me, Im not sure how long we had been kissing but when I turned to face forward again, I see my son standing there just watching us. It caught me off guard so I try to pull away to his but the guy had me pinned in a way that I really couldn't move. He just kept going at it, grunting and saying "you want this **, don't you? Take it. You know you want this **." After what seemed like forever, my son casually turns around and just walks out the bedroom...anyway, the guy seemed much more turned on and got a little more aggressive...it was actually pretty hot. After we finished he couldn't stop talking about how turned he was that my son walked in on us...I told him I felt weird about it but loved how turned on he was by it...anyway, the next day none of us mentioned anything about the situation and by the end of the day it just felt like an awkward moment....nothing more....Well Saturday night, we went at it again and he was a little louder than usual and kept saying "maybe he'll walk in on us again." and stuff like that. Nothing happened, we go to bed....I wak up the next morning and I noticed he's not in bed so I put some shorts and a tshirt on to get some coffee. As I go downstairs and turn the corner I see my sitting in the guy's lap, basically swallowing each other's tongues...as soon as they realize I'm there my son flys off his lap, full on ** in his shorts, then darts upstairs to his room. The guy is just casually sitting on the couch, part of his ** peeking out of the waistband of his shorts, oozing. He looks down at it, then looks up at me and just shrugs with this "what's the big deal" look on his face. I was completly caught off guard, a little turned on but mad, nontheless so I made him leave....I let a few hours pass to give my son an opportunity to get over whatever embarassment he was feeling and talked to him....My son admitted that he had been attracted to the guy for a while and they had been messing around for a couple of weeks. He said they had only really kissed and touched each other and that the guy had "licked his **" a few times....again, it turned me on a little but not in the sense that i thought it was hot, it was more about just hearing about what had happened....a couple of weeks pass and the guy comes over...we have a few drinks and he ends up staying over...For a good week or 2 everything is back to "normal" so I was starting to get comfortable with the situation until one Saturday morning my son said he needed to get some stuff for a project....he knew I had to work that day but he was just like, "well Mike can take me to get the stuff I need. I have to turn in the project by Monday" I told him we'd go out after I got out of work but he was deadset on Mike taking him. This was a bit odd because normally my son would be like "no big deal" So it didn't dawn on me right away but then I realized, either Mike put him up to this or my son is looking for a way to be alone with him...anyway i had asked Mike what he has planned for the day and Mike had mentioned that he actually had a meeting with a client that he absolutely could not cancel...this made me realize my son was trying to scheme something up...Mike literally seemed like he was not the one who put him up to this. The whole day i couldn't stop thinking about how anxious my son was about hanging out with Mike....anyway after work, we all have dinner, go to bed. We wake up, I go to shower and Mike goes to the kitchen and as soon as I get out of the shower, I come out of the bathroom just as Mike is walking out of my son's room and Mike just said "i was just making sure he's awake....odd thing is that Mike had a full on ** in his shorts... and I just looked at him and said "well it looks like it's quite awake." I'm mad but I just go get dressed and the anger is just festering but I don't know why, i call Mike upstairs, he is sitting watching the new...i'm standing outside my son's door...Mike comes up, I knock on my son's door and I really wasn't paying attention to what Mike was saying but he seemed a bit panicked....my son opens the door and I just say "you have a visitor"...they both look at me like "what?" I was just like, I 'm going to what, I don't care.....Mike goes to my bedroom and the kid shuts his door.....i'm getting all my ** together, made coffee and a couple of eggs...after i eat, I head back up to tell mike to leave but Mike is not in my bedroom anymore, I check the bathroom, he's not there and then as I walk up to my son's room, I hear what was either kissing or sucking....i just stood there listening.....it goes quiet for a while and right as I'm gonna walk away and sort this out in my head, I hear a high pitched moan and Mike saying "just leave it there, just wait" a few seconds pass, then another moan....the guy if ** my kid and I'm so turned on by it....after about 2 or 3 minutes I sneak away, and head for work....