He's afraid I'll get pregnant

My FWB says that with all the " sex" we are having I'm bound to get pregnant. He said that we need to avoid that by any means possible and that he's not ready for a baby.I'm on the pill and take it regularly. We generally use condoms but there have been a few instances that we didn't. The conversation came up because I expressed that I wanted to have more sex and that was his response. He is aware that I'm on birth control. He has mentioned this on more than one occasion. I have no interest in trying to get pregnant right now as I'm applying to grad school. I'm 29 and he's 34. Neither of us have had a child yet. In the past he has mentioned starting a family with me, moving to the burbs and getting married.I've never brought up having a child. He has on multiple occasions.