I found this in a book (need to find the book again as I can't remember the title) and I read it when my self-esteem gets low as I know that even with all my faults and short-comings in our M, I need to realize, that I did not cause my W to go out and have an affair. Lately, on most days I do realize this but I still have backslides and try to determine what I could have done in the past. This is something my IC and I are working on and I have made a lot of progress over the last few months.

"In the case of infidelity one person has chosen to break the most sacred oath you have taken in your relationship: the oath of loyalty. If you have been injured by infidelity, if your spouse took it upon himself or herself to go outside your marriage to seek fulfillment in some way, YOU ARE NOT TO BLAME."