Disagreement on how many kids we want

Not sure if this is the right group for this. And sorry for the long post.

My husband and I have always wanted more than 2 kids. We have 2 boys at the moment, 2year old and a 4 month old.

When I was 20 weeks pregnant with my 2nd baby, we got told at the scan that he had some issues which were pointing towards him having a genetic problem. We did an amniocentesis, and had to wait 5 weeks before we were told what the problem was.

My whole world broke down. He has a condition where his eyesight will gradually deteriorate, he had enlarged kidneys (which seem to be back at the right size now) he might have a learning disability, obesity and so many more problems in his life. It came as such a shock to us because my 1st boy is completely fine, I never expected for this to happen.

I grieved when I found out.

I grieved for any 'future' babies I wanted.

I grieved for the baby girl I so wanted but will never be able to try for.

I grieved for the fact that if I ever get pregnant again, it won't be full of excitement but rather stress.

My husband still wants to have more, he wants a big family because he was an only child.

It took a while for us to agree on how many kids we were planning on having. He wanted 5-6 and I wanted 3, so we compromised and said 4. Now I don't want anymore.

How can you bring a child into this world knowing how difficult their life could be? How can you do that on purpose!? He said to put your trust in God, and I do trust God wholeheartedly, but is it not silly and selfish to have more?

I spoke to him about us potentially having to be carers for our 2nd boy when he's older, depending on how severe his condition is and whether or not he has a learning disability, severe autism etc. Every time, he says "I trust God that our baby's condition won't be that serious." Which, don't get me wrong, it's great to have faith but God also tests people and gives them difficult situations to deal with, so saying that is just a cop out I think.

I, in no way, mind being a carer for my boy, but my point is that if we have another and they have the condition as well then we may have 2 children to be carers of depending on severity of the condition. I don't think I would be able to live with the guilt.

Edit: I just wanted to say, the geneticist that told me the diagnosis also explained to me that the condition has been passed down from me and my husband.

With each pregnancy, there is 1 in 4 chance that our baby will have the condition (meaning both affected genes, 1 affected gene from me and 1 from my husband). My 1st boy, either has both unaffected genes, 1 from both of us, or has 1 unaffected and 1 affected, making him a carrier of the disorder but not affected by it himself. I hope this makes more sense?