Incest?

My mil always talks about her big boobs. My children (M 20 F 16) and I find it very embarrassing and inappropriate. She (84) says that men get excited. She says that some men try to touch her boobs 🤮. My husband doesn't remember if she did this when he was a child. In my opinion he removed it. Now we are doing couples therapy. The psychologist says that he is a MEM (surrogate husband). Is it covert incest?