I sympathize with you. My situation is a little different in that my wife, I believe, is not having an affair. HOWEVER if she WAS going out having sex with someone else before she filed for D and then used OUR home as some sort of basecamp to replenish her energies to go out again, I don't know how long I would hold on either. You are the model when someone else says "i'm doing all I can". Just know that you, with what you are doing for yourself, can not say to yourself " I could be doing more".
If you do manage to hold on and employ the LRT to get you through this, you might be rewarded in the future. It sounds like, not only is she having this A, but maybe going through MLC as well. If that's the case, stats say those "distractions" have a duration. When it is over she may come back and realize your understanding of her situation and how you didn't abandon her. I don't know or maybe it's all a fantasy we are living in.
Then again, my male family mantra is "The cure for the hurt from a woman is another woman"
Me 43 W 43 S 10 (Special Needs) M: 14 yrs T: 18 yrs Bomb: 09/16/12 Filed for D: WHO KNOWS???