The phrase 'God doesn't send you more than you can handle' is a good way to dig deep for extra resilience when the going gets tough, it's a helpful idea at times.
But it's not body armour.
And sometimes it makes you feel at fault if you aren't coping, because surely this is your allotted level of struggle threshold.
So, it's a man-made concept that might be comforting but I wouldn't factor it into your choice.
When someone lovely dies early for a tragic reason we say 'they were too good for this earth and god took them early'...
There are devout people all over the world dying for all sorts of reasons every day. Some avoidable and some not, some too young and some not. Some for health reasons some because of the folly of man.
Listen to the medical advice, listen to your husband, listen to yourself - heart AND head.
It's not good your DH is threatening to leave, but I can have some sympathy if you're high risk, he must be terrified.
Not easy and I wish you the best whatever decision you make.