Problem is, they're almost always wrong. Even if the husbands themselves believe they're cheating because their wife isn't as sexy as she used to be, or as fun as she used to be, or as (fill in blank here) as she used to be, the reality is that he's cheating because something is missing in him. Something he thinks he'll find in another relationship or in a distraction.
But whatever he thinks he's doing -- or why -- don't fall into the trap of taking responsibility. If you want to make changes to feel better about yourself, that's great. But far too many of us change out of some misguided belief that if we were smarter/prettier/skinnier/fill in adjective here, then he wouldn't have cheated.
Me? I started dressing like a geriatric Britney Spears in a misguided attempt to feel sexy. Some even go so far as to undergo plastic surgery -- neither cheap nor painless. But when the scars healed, they were still themselves (albeit not quite so tired looking) and they still had to heal their hearts.
My advice: Focus on getting strong. Being kind to yourself. And treating yourself with respect.
It might be harder than surgery. But the effects will last a lifetime.