The more sex I have, the more I want. It's MY body, I can touch it if I want to. I think most people are like that. I've gone AGES without sex and not been interested in masturbating either, just not in that sort or mindframe at the time. As for how much is too much? Does it interfere with your day to day life, are you too exhausted to perform with your gf? If not, don't worry about it.