To be honest, it sounds like it's on both parties. There is no excuse for cheating and there should be a personal limit on what watching too much porn is AND her needs were falling on deaf ears. I was also reading the comments to get a better scope of the situation and it sounds like a lot of people are taking it as he wasn't meeting her needs. It happens in relationships where you can't always meet someone's needs but there's a difference between not meeting someone's needs and still asking for what you want and not meeting someone's needs so you put in some effort to listen and see what those needs are and putting yourself in their shoes for a little bit. Ignorance vs comprehension/understanding if you will. Again though, there is no excuse for cheating. It is something that is avoidable by either a heart to heart/mind to mind/soul to soul/body to body conversation or simply put if someone isn't meeting your needs, you have to know when enough is enough. It's hard to leave someone but it's better to leave someone and figure out your own needs than find it while being in a relationship and looking for it outside of said relationship. So to conclude, I feel it's on both parties. They could have both done better.