Say that again and again. You are a blessing to your kids, your students, everyone here, your family, your friends.
HOW ON EARTH did YOU ruin things? Were YOU the one who cheated? Left? Lied? Ripped a family apart? Lacked courage to do something?
No, that was your H.
Step 1 to your healing is NOT taking blame for things falling apart. That is life. Things happen. We make mistakes. Our H's make mistakes. We find explanations and take our share of the blame, but just OUR SHARE.
Wanna run away? Go teach in Africa?
How about something totally zany. How about doing a teacher/exchange program somewhere, even in the US, during summer break, so you and the kids get to live somewhere totally different, just ask room/board for pay, and you teach? There have GOT to be plenty of programs like that....maybe not now, but sometime in the future for the summer.
I am so sorry this is tough. But in the end, YOU will move on faster than he has. YOU will have more success than he has. No one who goes through this, thinking they did nothing, will prosper.