Boyfriend wants to break up if I don't have his baby

My boyfriend and I have been together two years, i'm 19 he's 25. We don't have any children yet, but we have had two miscarriages in the past year. I have a 3 year old son from a previous relationship. He loves my son but sometimes he gets distant, he will do things like ignore him, he forgets to include him in family trips/photos. He'll pay for my food but not my child. He said because it's not his child and he doesn't want to get to close, which I understand.

We have been trying since I was 17. His mom wants a grandchild really bad also. She's asked him things over the phone about me ( her not knowing I can hear their convo) she was saying things like "it's sad she can't carry a baby to term" & said me having a baby at 16 probably fucked my body up. Then asked him was he really sure about marrying me soon & spending the rest of our life together & I can't even "produce" or start a family.

It really hurt my feelings because I love his mom and I do want to be able to start a family soon. Idk why I had those miscarriages back to back. My boyfriend says it's because I didn't take my prenatal daily, which is true some days I would forget. But he said if I can't get pregnant soon then he don't want to be with me because soon he wants to start a family and have his own children with me. I am trying and it's really hard and stressful. It's definitely stressful taking care of my son alone, his dad isn't in his present & my boyfriend never wants him around really.

What should I do? Have anyone gone through anything similar?