I don't think this lack of sex problem has anything to do with hormones or sex drive. Some guys never touch their wives, yet are constantly whacking off to porn.
Its a relationship problem.
It might not be anything serious, but he has some reason to try to avoid you. Some guys feel too much pressure to perform, or look at it like work instead of fun. I have tried to understand it, because I am the opposite. I can't keep my hands off my wife, after 25.5 years of marriage, every day, all natural. We do it all the time because we are completely comfortable with each other. If a guy doesn't want to do it, the problem is probably between his ears.