He doesn't want kids....

My boyfriend and I are both 19 , we've been together for 4years. My boyfriend comes from a huge family his parents are divorced & both his mom and dad have 8 kids each ... Yes each... My boyfriends brothers and sisters have kids & their kids are brats and rude he says he doesn't want kids due to the fact that he would hate it if his kids were like that. We've always talked about getting married and starting our own family. Sometimes he'll be like we're only having one kid sometimes he'll say none At all. It breaks my heart to hear no kids at all or just one because I come from a small family & I hate it. I want a big family maybe 3 kids would be perfect for me or 4. He knows I want kids so I could just hope he's willing to give me what I want so bad. He's so good with kids & it's so beautiful to see him play with them. But this  All breaks my heart because I see myself married to him & having little ones.