Unpopular opinion, but guys want/need sex too. I know you’re recovering and I’m not justifying his actions. You said you haven’t been enjoying sex for a while, that more than likely means neither has he. If he is “watching too much porn” it’s probably because you haven’t been enjoying sex, so you haven’t been having much sex. He probably got turned on while y’all were dancing, misread something, was sexually frustrated, and now feels like an idiot.

I’ve been with my girlfriend for almost a decade. We had a couple years and times where it would be 5-6 months in between having sex. Watching porn kept me from wanting to cheat. Because I promise you thoughts of if we ain’t going to have sex more often she can go, I can live alone and watch porn has probably ran through his head. Don’t shame him for watching porn, he’s staying faithful.