I'm going to circle back and read your original thread, but thought you deserved a response first.
I am in a similar boat with the OW being unmarried. I fully intend to expose her R with my H to her parents. It is hard to say whether or not this will "do" anything in regards to your M. Her father may not put any pressure on her at all. When I took my ex OM home on vacation to my parents' house the only stipulation they had was we couldn't sleep in the same room. So no, don't get your hopes up that her dad will straighten her out. But maybe it's something he should know about your H. I mean, what kind of father wants a married man fooling with his daughter?
Advice on when and whether to expose the A is varied. But I suppose one of my questions is this - what do you stand to lose by it at this point? He's already going forward with D it sounds like. My other is this - why have you not exposed the A to anyone but your parents, but now really want to expose it to hers as well?
Ok, going to go read your original thread and come back.
undefeated 24 H 24 S's 4, 2, 1 M 5 yrs
"Most of the important things in the world have been accomplished by people who have kept on trying when there seemed to be no hope at all." ~Dale Carnegie