Based on the history, would my husband be happier with his ex mistress, or will he ALWAYS be unhappy?

I have to be honest with you: I think you have some serious denial issues. This man was ual with this woman for over a year. He told you that his texts to her of proclaiming his love was lies, but truthfully he was lying to you so the marriage wouldn't end. Not to mention he revisited the affair several times during a 6month period after swearing to you he'd forget her. The man is attached, and he has no reason to hate HER. Because she hasn't don't anything wrong to him? She's been his ual partner, a loving and supporting mistress, according to his emails/texts to her. Instead, any hatred or resentment he'd feel would be towards himself or YOU, because ultimately you're in the way of his affair with this woman. You can't lose attraction or feelings over someone because you're significant other wants you too. Whether or not he's tried to suppress them isn't known here, only he knows the answer to that. But pulling to the side of the road and meeting each other's gaze, he was probably hoping she would come over work things out. I'm in no way trying to offend or upset you, but this is a horrible situation that you should've stepped out of the moment you found out. You need to get some self respect and leave this guy to fend for himself and this woman. You're married to a cheater and deceiver.