She sounds like a serial cheater, and I think that it's very difficult for them to break the cycle. I would suggest that you both go into individual counselling. She needs to work on her issues as to why she feels the need to cheat, and risk breaking her precious family. And, you need to work on YOU, to find a way to forgive her (more for your own sanity, then for her, and not to excuse her behaviour), and GAL for yourself, so that no matter what happens, you will be okay. If she can show that she can prove herself to you, then I would say give her a chance, but I don't know how she can do so after so many affairs. It's more than her giving her word, which is pretty worthless right now, it's her actions, her level of contriteness, and how transparent she is with her everyday activities.
In the end, it might be best for you to walk away, rather than teach your children that it's okay for daddy to be treated like this.
Me:57 H:52 M:28 Got another lawyer last year and filed. D35,S/D twins28,D22 EA4/04 End? Who knows? "Life is like a mirror. Smile at it and it smiles back at you." — Peace Pilgrim