Yes, you need to ask him .... he's the only one that can tell you what's in his head. I too believe that it could be that he wants to save himself for marriage, or not have a baby out of wedlock. Understandable. It is better for you to choose to get married and have a family, then to have a family and then get married. I think he may be looking after both your best interests.
Have you asked him about it? What is his response? Some men don't want to risk getting a girl pregnant even if she says she is on birth control or if they use condoms (accidents happen) and some guys want to be super serious with a girl before engaging in sex and others don't because of family or religious reasons. So, ask him?