If you decide to stay & try to deal w/his problems, that for some reason he doesn't wanto solve to move the relationship forward, I can almost guarantee that you will start to feel resentment over the situation.
Sex is a healthy part of a relationship for you both. If you give up sex to be w/him, then why should be really bother to investigate the problem....if you're willing to go without.
Just my opinion.
Resentment will ruin a relationship.