DGDzDad - Your original question - Am I Wrong for Wanting D’s Relationship to Be Over? I say no, that’s not wrong. H and I secretly wished D would not date two of the guys she dated during her ten (or so) years of dating before she started dating SIL. The secret is secretly. We talked about it with each other, but never with her. I am sorry. It hurts when we have hurt a child. Your apology will be only the beginning of repairing your relationship with your D. I wish you and your family well and hope for healing.
I love this line from a movie on TV, my husband is watching, where the actress said "I’m an American, we’re not PASSIVE people. At the first sight of problem, we take ACTION. " The actress was in the Seinfeld show, I don’t remember the exact spelling of her name. The people she was speaking to was the security in the UK. Anyway the comment reminds me of this thread.
So don’t be passive, be an American, take an “I can so” pill, is what I would say to bf of OPs daughter.
MODERATOR’S NOTE
I think you’ve given the OP much to ponder. At this point, there does not seem to be much new to add. On that basis, I feel the time to close this thread has come.