Rae-
Disclaimer: This is not how I felt when I was in the middle of things.
Reality: My husband had an affair that finally put the nail in the coffin so to speak. I was FINALLY able to put up some boundaries around the affair that I could not manage around the alcohol use in my marriage.
In reality though it was INCREDIBLY painful the affair was a blessing. He married his affair partner very soon after our divorce (within months). Though I ached and hurt when I heard about his new upcoming marriage it allowed the romance of "What if he finds recovery...." a little less place in my mind.
It helped to force me to keep the focus on me and my healing, and in the long run THAT has made all the difference.