I am sorry for your lost pregnancies, op.
I still do feel that choosing for your dd to grow up in a one parent family, and be spending alternate weekends with her mum and dad in their separate dwellings, and negotiate over time spent where and for how long during holidays, "just" because you want more children, is unfair on your dd.
Dont railroad your relationship over this issue. Sometime, being an adult and being a parent means that you have to compromise. He might have compromised with this one child, like you are doing now.
But I think you need to have a serious talk with your husband about this. Not an argument, but a sensible calm grown up talk.
I am 39, I have two children. My dh wants a third. I dont. I honestly dont think I can cope with 3 children. I can just about manage to handle and give attention to the two I do have. One more will mean that all three children will get less attention. And I may lose my temper more, and be a grumpier mum, which is not fair on neither 3 children, nor my husband.
It is serious consideration, one that deserves a proper analysis from all your angles.
I friend of mine has two children. She is 40, the oldest is 5 and the youngest is 2. She married a man with three children from his first marriage, the oldest is a 19 year old girl who lives abroad, the other two are boys of 15 and 14. She refers to all as "our children". They have shared access, so the boys live one week with each parent. The parents live near each other. All three adults are now good friends. (Marriage broke down as they realized they were friends, as passion had gone.) To complicate this scenario a little, his ex has a 5 y ear old boy with a new (but now ex) partner, and he was born 2 days before my friends 5 year old. So, 6 children in this mix. And a happier mix I have never seen.
They ALL spend Christmas together. The 5 year old as best mates and go on sleep overs to each other. These three adults are so down to earth. I am so amazed at how well they manage to work out their life together. My friend accepted that the oldest three children (and in fact the ex wife) came as part and parcel with her husband.
So, how close are you to your husbands children? How old are they?
Again playing devils advocate, could your relationship with his kids be a reason he does not want to have more children? If you want more kids, why not spend more time getting to know children who are already here?
(Please bear with me if I am out of line, as I know nothing of your relationship with his children. I am just trying to bring some thoughts in)