I agree. It would be hot for me to find out that my Uncle fucked my first wife, If he did, I hope that he got to fuck her several times. When I think back on family gatherings from that time, the thought that my Uncle was fucking my wife is very exciting.
As discreet as we tried to be, our kids discovered our lifestyle too. They probably suspected before either of them mentioned it to us, but our son asked us about it when he was 18 and our daughter when she was 16.
I tried to get my first wife and Kate to have sex with my younger brother but neither of them was interested in him. My wife Kate has had sex with one of my male cousins and the husband of one of my female cousins (many times). I have five married male cousins and they have all seen my wife Kate naked. I put together a cousins golf outing with food and drink at my house afterward. I knew Kate would be the only wife at the cookout. Kate is younger (and hotter) than any of my cousin's wives and I knew they all thought Kate is hot.
When we finished golfing we went to my house and Kate had food ready. We had a swimming pool so Kate was in one of her tiny bikinis. My cousins were happy to see Kate. We ate and drank for a while then we all ended up naked in our pool. My youngest cousin lived out of town so he was spending the night with us. He got to fuck Kate while I watched after the other cousins left.
My brother (and the other cousins) heard about our youngest cousin getting to fuck Kate after that party. I know that Kate will not have sex with my brother but I have shown him nude pics of her and pics of her having sex with several different guys.