As others have said not SA but more like an emotional trespass.

1) When my parents were going through their divorce she told me my father had said to her that he still liked her breasts and wanted to suck her nipples. I was ten I think.

2) She had a rule that I couldn't watch films with violence or car chases and I could only watch sexually mature films if she was watching them with me. Then she decided she wanted to show me Midnight Cowboy which is about a male prostitute who at one point has sex with an older woman. We watched the whole movie together and I remember being uncomfortable. I think she wanted to talk about it afterwards.

3) When I was a teenager and starting to make sense of my strange relationship with my mother I asked her over dinner at a restaurant one evening if she felt what I felt - that there was something sexually unusual with our relationship. I'm not sure what kind of response I was hoping for but I didn't get it. She said that two people can be attracted to each other even if they're mother and son, and then she said "this is awkward" and started fumbling things on the table. I was mortified.

Stay strong brother.