Advice needed, cold feet about babies

Amy
Hi ladies, I'm in a bit of a conundrum. My boyfriend and I were ttc, and with my Pcos and previous cervical cancer I beat 3 years ago, we knew it would be an uphill battle. I went to a specialist, and the first month after, we were like rabbits. Now things have just fizzled into nothing. He talks about our future with kids and stuff like its thus far off distant time, and keeps saying things like "if it happens, it happens" 
My biology is not the "if it happens" type. I've known that since I was 16, when I got diagnosed with Pcos, and the cervical cancer. Exacerbated my desire to really have just one baby. It's all I've ever wanted. I know it's going to be difficult, and fun, and sleep deprived and sad at times, but I'm ready for the teething, the blown out diapers, the whole bit. 
I just feel like my bf thinks we have all the time in the world. I turn 36 in April, my mother went through menopause at 40, we barely have any time! 
I don't know what to say to him to try to figure out what he's thinking, or why he has cold feet about the whole actively trying all the time thing. (For two months he picked fights with me while I was ovulating, and then we had a false positive/chemical this weekend that turned out to be nothing) I asked him if he really wants it at all and he repeats the if it happens line.  How do I tell him, without saying the actual words, that we need to be on the exact same page here. (Since I just did that.) I'm at a loss.
Help!