I am no psychologist, therapist, or psychiatrist, that's for sure. But I do have a PhD in being on the bad end of infidelity/straying/whatever you want to call it.

No idea how an"open" relationship works, especially with it being committed on one side and open on the other. That just sounds like a mess to me.

The real damage to a relationship between any two people in any type of perceived straying situation is not the sex. It is the lying. Every so often, it is a once-in-a-lifetime move of stupidty that will never happen again. I have seen this once. More often than not, though, people who cheat and lie, cheat and lie. Hence, the saying--cheaters cheat.

It would seem this type of behavior has been shown to be who this woman is, irrespective of how great a daughter or how charming or interesting or whatever she is. You are just going to have to decide how much grief her company is worth. I stuck with someone who was a serial cheater and she is who she is. Should have left her way, way before I did. Those people are nothing but heartache. At their core, they really are all about themselves and their own impusilve wants. Quick sexual thrills are more important to them than relationships.

Hope you do what is best for you.