Jill - since you asked the question here, I'll put my two cents in here on forgiveness. First - you won't forget but you do have to let go.Especially in your case - this didn't happen because he's a dog who feels entitled to have multiple partners - it happened because he was lonely, felt he was losing the "old you", felt unappreciated, whatever - doesn't excuse it, but it came from a place of weakness in him. The other thought I had once is, men live in a completely different world in terms of opportunity. It is easy for us to say "oh, I'd never do that to my spouse" - but honestly, how much temptation is a housewife with kids subjected to? Imagine for a moment that you live in an alternate universe. In this universe, most women stay pretty fit and attractive into their 50's, while the men they marry frequently acquire large beer bellies and quit dressing nicely, etc. And imagine that when you go to the grocery store, that cute young checkout boy with the washboard abs makes it clear that he's available. And the handsome waiter at your favorite restaurant flirts with you and slips you his number? If this went on all the time - or at least the possibility was clearly there - would we really all be as virtuous as we claim? Especially if our sex drives were revved up to twice normal?
I'm not excusing it, or saying it's fair - but try judging it from HIS universe instead of OURS.
The only thing that will make you feel better in the long run is when you have a long history of loving behavior from him to look back on - just don't keep making him pay and pay in the meantime, or you will drive him away. For now - get your anger out in lots of exercise!
Ellie