I've just want to give you a massive hug.
The trick is to keep breathing, you have been so strong for so long. Nothing I can say will fix it but please know you are not alone and it's important to know you are already doing so much by being there. It's okay if you need to take some time for you too, do not feel guilty... I can feel in your words how much you love him and nothing will change that.
On a personal note, I recommend trying to do something you used to enjoy, even if just for a few hours a week... gardening, cooking, crafting or catching up with family/friends, maybe even watching some shows you like, whatever it is that you can lose yourself in for a bit. And go easy on yourself, emotions are tough but they are healthy expression of how you feel, sometimes you just gotta let it out. Its just not easy, but there is a great deal of support on this site, x