How is it NOT about me?

I have this question running through my head and I'm going to try to articulate this but it may be tough. Everything I read during and after my husbands online affairs kept saying that this was the cheating spouses issue not mine. He was looking for something to avoid issues of his own and this was not caused by me nor could I have prevented it. I see an ad this week for a program that will affair proof your marriage. When I started looking into this I found that this is a pretty popular trend. I found 3 books, 2 programs and a DVD on affair proofing your marriage.  So this tells me It's not my fault nor did I do anything to cause him to stray BUT there are things that I can do to keep him from cheating so I must have not done those things which would put this on me right? See where I'm going? because now I'm dizzy.  I resent the idea that had I been doing something different or right he would have made better character choices.  How about this, You failed to check your backyard gate daily like you should and your dog was in the street for the 3rd time this week so I just chose to run over him.   It was the wrong thing to do but had you done something differently I wouldn't have been forced to make a bad decision.  Am I wrong or is this more of "it's someone else's fault"?   My husband went through a bout with depression, I panicked and working in robot mode I wore myself out doing everything in my power to keep things level, stress free at home, calm and whatever I could do to keep him from worry.   I shut out everyone and everything and focused on that.  I stayed mentally and physically exhausted,we didn't communicate and rarely touched but I was determined that he would not be stressed.  He felt shut out and I was bitter and he turned to other people.  Did I make a bad choice?  Yes, Did he make a bad choice, Yes.  Could he have chosen to respond differently, Yes.  Should I have just let him feel pain like an adult?  Yes. Can I read a book, make some changes and keep someone else from making bad choices? NO.   Don't put that off on me.  I know I could have done things differently but it doesn't justify his choice.   If you have some knowledge of the affair proof plan and could correct me on my view I would welcome the input.  The pain of being betrayed is hard enough, it cuts through your self esteem and makes you question things you never imagined.  I truly believe that he made a choice and if that's what he truly wanted to do he would have found an excuse even if I had made the perfect choices all along.