My boyfriend and I never argue, but sometimes he looks at porn and I get very upset for days!! what can I do?

He is very good to me and my two children. I know that most guys look at porn, but it makes me feel inadequate. He works alot and is tired most of the time. We have great sex on a regular basis(twice a week) but I want it more than that. I feel that if he is too tired to have sex with me more than what we do, then he should be too tired to look at porn.