Im probably going to raise a different view point to most here. So far, trying to bring a currently non existent being into your life, has caused you the misery of 2 miscarriages and is now threatening your 20 year relationship.
If I was your husband, I wouldn't want you to go through that again. And I wouldn't want to either.
I mean, if your life is happy together, why does it need anything added?
If I were you, I'd be asking myself if a currently non existent person was more important than my relationship? (And arguably my physical and mental health?) If, i still felt yes, then I'd be questioning why?
Have I been conditioned into thinking that women need children to be, what, women? Complete? Fulfilled? Why am I doing something that is harming me, my partner and our relationship?
I'm not saying that having kids isn't a genuine calling for some. But I think sometimes people get carried away with the idea of an 'ideal' when really, they should appreciate what they have. Or, they try to fix something lacking, like a bad relationship or failing in some other dream pursuit, by adding kids.
Maybe just consider if thise things are a possibility.