What else could I have done?

[antlers]

OK Barb.
I was struggling to save my marriage and family, while she was screwing my son's basketball coach! One of many infidelities during our marriage. And her lies and deceit placed ALL of the blame on me. She convinced my kids, and even me, that ALL of the blame was mine. And I took ALL of the blame for a very long time. Her wrongdoings did not diminish mine. I shouldered mine and did something about it. It took me 3 years before I could truly forgive myself. So yes, forgiving her would be a very difficult thing. She "hates" me to this day...and has not shouldered one ounce of fault. As long as it's 'all me' that did wrong, it was none of her. And she refuses to forgive me at all. 
If it will help me to feel better for them to finally know the truth, then I think it's OK under these circumstances. I don't need to put her or her mother's needs and feelings above mine right now. I am allowed to be angry about this and there's no reason to protect her or her mother from the truth.
I've felt awful and beat myself up for 3 solid years. I took ALL of the blame for years! After she left and destroyed our family I still put her needs above mine for years...even when she was doing what she was! If it's about me, then so be it! If it helps me at this stage of the thing, then so be it. I don't think telling the truth is bad, especially under these circumstances. Her wrongdoings don't diminish mine...but they counted too!