I changed the names in the story. for context: OP is a 40 year old swinger male

I met this beautiful mature lady (I will call her Tina from now on) at a private swingers party. we had a very good chemistry and had a lot of fun. We ended up exchanging numbers. A couple days later I received a message from her, asking me to meet her at her place. I was really excited. So excited that I even shaved my beard (IYKYK). I was ready for a long night with this gorgeous woman. Previous sentence predicts the rest of the story pretty well in terms of length and the company, except for the fact that I was not ready for what to come, no one can be.

She met me at the door. Invited me in and asked if I would like a drink. After filling up our wine glasses she came back to the table with 3 glasses of wine, instead of 2. I looked at her and was ready to ask what was going on but she placed the index finger of her right hand on my lips and made a 'shhh' sound. She pointed at the door to her room and then said 'come in'. I was watching clueless, when a young boy, a very well hung boy (I will call him Tim from now on) came in through the door and hailed me by nodding his head. Tina turned to me and said 'don't say a word, just watch'. She got up and brought me the wine bottle so that I could top up while watching them.

I will not go into details, but they made sex all night, in every possible position one can think of. I don't remember the number of times they came, synchronously, separately, consecutively or randomly. I drank whole bottle of wine plus a couple beer. Tina told me to stay and watch them until morning. By the time sun started going up, Tim asked for her permission to leave and she granted him the permission. As Tim was leaving the room, he turned back and said 'sleep well ma', and left the room after that. I giggled and said 'hah! still role-playing ha?' turning my face to Tina in the meantime.

She was very serious. She was looking at me like a scientist looking at a new type of species. After scanning my whole face several times, she started smiling and said 'hah! joke is on you, he is my real son. you are so naive daddy!' I was appalled. I could not talk. Just stood up and left the place (note that I was pretty drunk). I went home and slept over it (thanks alcohol). But I am not able to sleep since then (It has been 4 days since the incident). I see them when I close my eyes. It does not go away.

Am I wrong in feeling disgust? Tim is well over 18 (Probably late twenties) so I don't think that can be made into a case. I am thinking of exposing her. Is that the right thing? I am very confused. Was that abuse? Was I abused (I was there by my own consent until the very last minute and they did not try to stop me when I left)? what would you do? How would you feel?