Romantic interest doesn't accept himself and it hurts

Hey first post ever, but I am seeing a guy who has a lot of similar interests to me and we have been taking the whole process of seeing each other very slow (only kissed him for the first time 2 weeks ago) and he says now that he can't pursue anything beyond a friendship because he has problems with being himself/gay. I want to help him see that there is nothing wrong with being gay and that it is okay to be with a guy, how can I help him? Relationship facts: we've been seeing each other for about 2 months, hangout a lot, and talk a lot about everything.