I totally understand the feelings of betrayal. For me, even 2 years on, it's the deceit from when we were together that is the most painful thing. And I understand wanting to hurt him back. Although it's unsatisfying in an immediate sense, he will end up hurting chronically from this- he'll always regret what he did, but you have a chance to move forward knowing you did EVERYTHING you could have. Eventually your kids will understand the things he did and they'll know why the M broke up too. He will probably never recover from this.
