I wonder just how "set for life" she really is. As you say they've been together seven months and that her wedding ring was replaced when they returned from that last trip, I am assuming that as yet, the two of you haven't legally divorced, which means they aren't legally married.
Even if you give her a divorce, there's no guarantee he will marry her and take a chance on her being entitled to his estate. So she may just find herself flat on her ass someplace down the road, if he gets tired of her or simply wants to make another conquest, since he already won her. His thrill might be taking white wive's away from white husbands, once he wins one, it's time to dump her and go after another.
It will be interesting to see what happens if and when you get divorced. I wouldn't be too surprised if someday to to long afterward, she shows up on your doorstep.
Will, I can't dispute what you say at all. I am going ahead with a divorce. According to my wife he has set up finances that she is set for life. He has paid off all her bills. She has a credit card to get cash or buy what she wants. Of course this can all end in a instant. She has a MBA, I'm sure she was careful to be sure that what ever "finances" were set up for her are real. So if he does dump her, she does come out in pretty good shape, from what I understand.