You said: 'Both girls are of age...." Me: You waited too long. My suggestions: Let them see your wife and her bull being intimate. Invite him for dinner and explain to them that mommy has a friend she's very close with. But also let them know that your marriage is strong and there is no intention of getting divorced. Let mommy & bull be slightly affectionate with each other.....hugs...holding hands....kisses that start-off short but soon become longer, more lingering. Start slow. Dad should casually joke....'Look at you two.......I think I may have to sleep in the guest room....*chuckle*...' Make the situation light-hearted. Let the girls know that your marriage is fine, but that it's important for mommy to be happy. After dinner, while watching TV in the living room, mommy and her bull should sit together. Let your girls hear the soft, wet kissing sounds that mommy and her bull make. Also important: Mommy should be dressed provocatively. Not as if she were going clubbing….but something low-cut….and short. Make it easy for her bull to let his hands roam freely. Let the bull charm your daughters to see that he’s a good man who makes their mother (and father) happy. Eventually, convince your daughters to dress – and behave – accordingly. Have them greet the bull warmly. Mom & dad should suggest that the bull give their daughters proper kissing lessons. They shouldn’t complain when his kisses become more intimate…or last a bit longer. If he undoes a few buttons on their blouses, that's fine. If he openly caresses that ripe asses, great! They should smile at him and happily accept when his hands explore their young bodies. And dad should always let his girls know that all is well. I have more ideas, but that’s all for now.