So...she "fell in love" with these guys but never told them how she felt and never had any physical relationship with them. How did you find out? Did she come out and tell you she was "in love" with another man?She saw enough reason to humiliate me by falling in love with a friend and my brother, never did anything sexual with either of them, or even told either of them how she felt in so many words.
If you've grilled her for details in the past, use that info to try to understand what she was missing from her emotional relationship with you that she felt she was getting from them. She should do the same. You two desperately need counseling. Even if you ultimately divorce, it sounds like you have major self-esteem issues which will not magically resolve themselves on their own and will continue to plague you down the road.
If you know positively that your trust in her has been permanently damaged, the only right thing to do is to divorce her. Otherwise, you are sentencing yourself, your wife, and your kids to a lifetime of resentment, poor communication, and malcontent.