I am right there with you girls (unless I am drunk, then I am usually horny and not embarrassed about my body). I have always had this problem for as long as I've had a sex life. It isn't that I don't enjoy it, it's just usually I don't feel like it. Then once we start, it gets easier. Matt has a real problem with this, thinks I don't find him sexually attractive, when I do. So it's definitely taken a toll on our relationship, but I think he is finally realizing that to me sex does not equal love.
Oh and re:bc - mine used to get better once I went off bc, but that doesn't have really any effect on it anymore for some reason...