I would encourage you to do some reading about affairs. They are HIGHLY addictive; the endorphins (PEAs) that wash over a cheater's brain even show up on CAT scans.
And I don't know of many (any?) addictions that just end on their own. In fact, most escalate, and do a lot of damage along the way.
My wife and I went to a small-group, in-home parenting series once at some friends' house. And the woman on the videotape (yeah, we used to have videotapes back then, lol!) said something very wise that has always stuck with me. When presented with how strict-vs.-lenient to be with her then-teen daughter, she would tell her daughter "I care more about what the 25 year old Lindsay thinks than what the 15 year old one does."
She explained to her daughter that she didn't want her 25 year old self coming to her mom, 10 years from now, saying some version of "WHAT THE H*LL WERE YOU THINKING LETTING ME DO THAT??!"
Your daughter is at a VERY formative age for how she is going to relate to men, and how she will "teach" people to treat her. I don't need an answer from you right now, but I'd encourage you to strongly ponder:
How would you counsel the 26-year old version of your married daughter, if she came and confided to you the same situation that you and her father are in right now? What would you tell her to do?
