I wish my mom would stop bring up the cheating

I know my mom loves me and hurts for me and wants whats best for me, but she continues to bring up my husband's affair. She'll bring it up to us, family, at family get together, even to strangers! I understand she's hurt for me, but I let it go, so should she. 18 years ago my husband had an affair. We've moved on, we've worked through it. Lots of marriage counseling of course, and since then we've welcomed 3 beautiful children and my children don't need to be told constantly how horrible their father is for cheating on their mom. I keep telling my mom to let it go, stop bringing it up, move on, but she isn't getting it and says she can't believe i stayed with that pos. Well I did mom! Now move tf own!