Is it normal to want him just for sex?

Me and my boyfriend have been dating for a year or so. We have only had sex twice and we only see each other on weekends. Well when I see him one of the first things on my mind is sex. I hate it. Usually we don't because I resist the urge. Sometimes when I'm not with him I want to have sex with him. Ugh. But is it normal to feel that way???