I had a similar situation happen. I reunited with an old 'friend' through FB. It's a long story of who he was to me years before I met my husband. Long story short, I only liked him as a friend, but at a very low point, I had sex with him once (it's complicated).

So, now, many years later, we were both married with children. He lived in my town coincidentally, so the families became friends. I had them over for dinners and our kids became friends.

Then he hit on me. He said he was only staying with his wife because of their child. He said he always 'saw us being together'.

I had zero attraction to this man. Had I, I can't say 100% what I might have done. Consider the very low place your mother may be in a marriage that you have no idea about.