Help! My fiancé changed his mind...

Kaitlyn • Surprise! Baby number three on the way! Twin sisters who are about to both become big sisters!
So we're laying in bed last night, and although now is not the "optimal" time for conceiving, sex was just going to be fun. Suddenly he's distant and doesn't want it. Before I know it, our conversation has lead to me finding out he's rethinking trying for a baby!! 
​We've only gotten to try for two complete cycles, and now he wants to give up. Not only quit trying, but possibly stop sex altogether until we get married (which there is no official date set for, spring 2015 was talked about). 
​Help! I don't know what to think or how to react. I want to keep trying for a baby so bad, and let it happen when it's meant to. I totally did not see this coming. 
​Any advice? I'm pretty dumbstruck and went to bed crying silently last night.