Why won't my boyfriend be intimate with me?

You haven't really talked to him about this, besides perhaps suggesting & him stating his tired. You need to ask him whats wrong, whats stressing him &n why he doesn't want to make love to you because really being tired can only take you so far. It might be that he doesn't have the stamina & in that case perhaps joining the gym is a good idea to get your energy back & changing your diet