As to the other issue - basically, the "once a cheater always a cheater" scenario~
When I was younger, I believed this, I also felt as strongly as you do, Acedawg, that I would never stand for it - that if my husband ever screwed up that way, I'd be out the door!
While thankfully, I have never been faced with that, I have seen many who have. Some have chosen to chuck the bum out, some have chosen to work through it
IF the guilty party is
TRULY repentant and knows they screwed up big time. I have seen marriages get stronger, but built on a different foundation. And now I'm not convinced of the "once a cheater" thing.
Anyway, my feelings have changed. I hope to high heavens that I'm never confronted with this situation, but I don't think I would have the knee jerk reaction to it that I would have had in my 20's. It all depends on the circumstances and the relationship.
Just my 2 cents.

I'm getting way too deep here though