Scared Dad, Hi, and I'm sorry you're here, but glad you are too.
I don't post much on SI anymore, and hardly ever in JFO, but your story caught my eye, and I haven't been able to stop thinking about it. Please pardon my presumption, but maybe you'd like some perspective from a child who grew up watching a situation very similar to what you're living with now.
My mother had affairs, and my father always forgave, or at least forgot, and my brother and I were the 'reasons' why he did, it was all about fulfilling a Christian image of marriage. In reality, it was about his fear of being alone, and his inability to face a future so different than he'd thought it would be.
The worst part wasn't when she'd leave generally, as devastating as that was; but in the times before, as she'd withdraw, as she'd justify her connection to another man, the way she'd scrabble desperately for any little thing she could use to make herself feel her actions were all right, even try to involve my brother or myself. That feeling of insignificance, of knowing that my mother was sick enough to be incapable of loving me, could use me and couldn't seethe damage she inflicted still hurts to this day.
What this has meant for me as an adult is huge. First of all, it set the stage and example for what I felt was an acceptable marriage - poor communication, disrespect from both parties, basically, that the only important thing was that it looked good from the outside. Read my story, you'll see how that worked out.
Now, working through the process of reconciliation has opened so many old wounds - my fWH says by having an affair he ripped the lid off the box I kept my old pain in, and it's so painful and hard to watch me try to sort that out.
You know who I'm the most angry with though? Not my mother, I've accepted that she is a sick, screwed up woman, damaged by childhood abuse and unable or unwilling to do the work that was necessary for true healing.
But my father, him I'm mad at. He used my brother and I as a shield to hide behind when he wasn't courageous enough to deal, and so we were hurt over and over again for years. He was the sane one, he was the one who was supposed to protect us, and he didn't, he couldn't, so he too put his selfish desire to pretend everything was all right above his children.
That sounds harsh, I know, but my parents are still together, still ignoring the past and living like strangers together, both seeming very unhappy, and both seeming very trapped. And once, my father said to me 'I often wonder what would have happened if I hadn't let your mother come home one of those times, where I'd be now; probably someplace better.' And then he clammed up and has never said anything about it ever again, except the advice a month from my DDay that my H and I should never think or talk about what he did again.
(No worries, we talk and deal plenty, still in IC, still in MC)
You are at the point where you can do what so many fail at - you can truly protect your children, right now, and for the future. It would be very nice if your wife would step up and be a good parent, either through R or a reasonable divorce, but right now she can't or won't.
But YOU are enough, you taking a stand for yourself and your children is enough to protect them, to help them in the future when they look back and realize that you loved them enough to put them first, and enough to take care of yourself so they could have a good strong father.
What you need to do is not petty, not vindictive, and not selfish. it is the right thing to do, as a father, and as a man.
Hope this helps a bit, you seem strong, and I think your kids are lucky to have you.