It depend on 果個女仔 really love your uncle or not. If you uncle still love your auntie and just ask your auntie 隻眼開隻眼閉. Don't give any pressure on her husband cause after 2 or 3 years, 果個女仔 may find out there are so many good man and she may finally give up on your uncle. Your uncle may go back to your auntie at the end.
So, just give them time and I don't think the girl really want to marry your uncle. But just want someone to care her....
Cause I know exactly the same case just like your friend's case. Her friend found out her husband has affair and she forced him to make decision and ask him to give the phone number her to call her husband's girl friend. Her husband finally divorced her and married the younger girl
So, ask your friend take it easy and don't force her husband.....