Christian morality vs sexual repression

Is Christian sexual morality unhealthy or unnatural? I'm young woman who is trying to live a chaste life, but my boyfriend is always pressuring me. He says that my concerns about sexual morality are just an expression of an unhealthy "fear"-that in trying to live by God's standards, I'm basically rejecting the beauties of creation and avoiding the joys of life in the flesh as God intended it. I'm finding it harder and harder to answer him when talks this way. Can you help me?