Often Wonder

This happened years back. I was a divorced mom and with a young son, and I had a neighbor who was my age and also was divorced with a son the same age, so naturally our boys were friends.
This was really the only reason why I spent any time with Cindy, because she did live close and our sons were friends. I did not especially like her very much. She was rather brash and I always felt like she was putting me down for being the quiet type.
One morning, over coffee, she sort of let slip how her son was taking care of her needs. I don’t remember exactly how she put it, but that was the gist of it. I could only assume that she meant she was having sex with her son, and of course I was shocked. So much so to that I didn’t want to know any of the details, so I certainly didn’t ask.
I remember that I went home with images in my mind of Cindy laying there naked, fucking with her son who was only about eleven at the time. Of course somehow with Cindy being the way that she was, I knew that I shouldn’t be surprised.
Needless to say I very much cooled over the idea and spending any time with her and my thinking this. I was so fearful that my son would learn about this from her son, and that he might want to have sex with me, thinking that this was okay and what mothers and sons did.
Thankfully Cindy moved away shortly after that time, and frankly I was relieved. Apparently my son never found out about any of this, or if he did, he never said, and thank heavens he never asked if he could have sex with me.
Over the years since, as this was decades ago, my shock over the idea of Cindy having sex with her son wore off, and I started to view it somewhat less critically. Actually even thinking that it was just Cindy and her son having some fun together. I have even imagined what it might have been like if I had been having sex with my son back then. Certainly it would have been convenient and probably fun to share that sort of physical closeness as mother and son. Of course, this was to say nothing of the emotional consequences, especially if I had done this with my son at such a young age. I know that I would have undoubtedly felt very guilty and like I was taking advantage.
My son is of course married now, and has been for a long time, with children of his own, and I have always been mom, and now a grandmother. I just wonder what he would think if he knew that I even had such thoughts? He would probablybe shocked.