I don't know if I should be honored or appalled that you hear my voice yelling at you silently! But since you've asked for help, I'm going to assume the former.
You didn't say, but are you feeling the same way that Hellkat indicated? Being played for a fool?
You also asked for another perspective. I'm not saying this is a good one, or the truth or something you should spend more than the time it takes to read it... okay?
Quote: Unfortunately, during my bad days, I really get stuck on this 'why' of the a, and 'why' he is unable/unwilling to understand the root cause of so much hurt in our lives.
What if the reason for his affair was good? Or what if it were bad? What if he doesn't have a reason? Or the absolute worst case scenario? What if he points to a behavior of yours that drove him away? Not one of these answers is going to bring you peace, honey.
I repeat: I AM NOT SAYING ANY OF THIS IS TRUE NOR SHOULD YOU CONSIDER HEADING DOWN THIS TUNNEL.
Okay, back to our program already in progress.
Slowly, something is ailing you, sweetie. Why is the "why" so important to you in your musings? I'm not beating you up--there are days when I really ask myself the same question. But since it appears that I'm not going to get an answer--or at least anytime soon--I really have to employ some thought stopping mechanisms to force me to change tracks.
You've listed some really wonderful positives, friend.
For some reason, the words of the counselor from my Parenting After Divorce class are tuning in to my frequency to share.
The happiest people are the ones who live in the present and spend little (if any) time focusing on the past.
It appears that you've still got an irritant that is preventing you from fully dismissing this A and forgiving him?
Slowly, one of my thought stopping mechanisms when I head down this cheeseless tunnel is to say, "Stop! You have already forgiven him for this! Now think of something else that's happier and more real!"
It's usually just enough to jar me into thinking about something else totally different. Like my friends. Or my weekend plans. Or some other problem that really needs my focus and attention.
If you had to guess, what would you say this little thing might be?
Sorry for the jarring words. They are not meant to buffet you when you're feeling low. I just want to point out an alternative perspective that may trigger some idea on why you're stuck here.
Big hugs. And may yoga calm you to serenity.
Betsey
"There are only 2 ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracle."
But since you've asked for help, I'm going to assume the former.
Betsey 
