wow sad story, especially when there are kids are involved. sounds like her getting involved with this guy has caused a big rift in your marriage... you have done all that you can to try to salvage this marriage, and she wants to MOVE ON.... you need to focus on being a strong daddy for your kids. its not easy but all i can say is ONE DAY AT A TIME... and know in your heart you were a loving, accomodating husband to her..... focus on your kids. and maybe seek out some therapy too to help you get through this.

take care