Mainly our son is keeping us together. Not wanting to split up the family. Hope that she will finally get it. And second guessing my own assessment of what's going on.
Totally understand these feelings, Panda. I did the same thing for the first two years. The only reason we separated was because I had an opportunity to do it in a partial way that protected our kid (I moved out to be closer to her school on weekdays).
The hope that "WS will finally get it" is very hard to let go, but at some point you'll have to accept what is rather than what could be. And sometimes, as in the case of my WS, even after he "got it", his understanding didn't last. After a few months of real change, he started sliding back into old habits. This repeated a couple of times, usually after I got really upset and stated a desire to separate/divorce.
Living for a future that never arrives is very frustrating, and ultimately, it's your life that's slipping away while you wait. Yes, divorce can be very hard on children and the wider family and social circles, but as they say, nothing will change until you change something. If you're frustrated by her actions (or lack of action), and you've done what you can, then it's okay to walk away. Millions of people get divorced every day, and it's not the end of their lives. Often, a year or two later, they feel much better. Kids might struggle and suffer for a year or two, but they will also learn to adjust and move on.
Imagine if your wife died next week. It would devastate your son, but you would help him get through the grief and learn to thrive again. The same holds here - you don't need to blame yourself if you need to divorce. That's on your wife because of her infidelity, which was her choice. You choosing to divorce her is a direct consequence of her actions, and certainly not one made hastily or for frivolous reasons. How old is your son? My daughter was 15 when we told her we were getting divorced, and 16 when I told her about her dad's cheating. She understood right away and didn't blame me for leaving him (in fact, she said I should have left right away). Your son's reaction might surprise you.