Would you divorce over this?

Let me start by saying i have had these feelings for a few years. I am a mother to a 9 year old who is not biologically my husbands. So in the beginning of our relationship he asked what i wanted in my future and such. I told him marriage and children were important to me and he agreed saying they were to him as well. Well we've been together almost 7 years and married for 2 (he's 29, I'm 28)and anytime i bring up that i still want a baby even later on down the road he shuts down and won't talk to me about it. I dont try to force him to have one, we use protection every time we have sex and that's fine by me but i do mention every now and again that having a baby is still one of my goals. I get this feeling in my gut that he just told me in the beginning he wanted kids just to make me happy, that he doesn't or never did want kids of his own and that bothers me. He refuses to talk about babies in any way, shape, or form and i don't understand why. Why can't he just be straight up with me and tell me how he feels about it? I just want to know what happened between the beginning and now..... im so lost. Is this a deal breaker kind of thing to some and not to other?. Any advice is appreciated.