That's interesting...that he is the taker and you the giver. And difficult that he looks to you to be his rock when at times that's just what you need, especially when you have to struggle with MI.
I don't know whether that dynamic can change for you...people can change the way they relate to each other, of course, but they both need to be open and willing.
Maybe when you're feeling in a better space, that's something to explore. In the meantime, I'd act like the taker! It's okay to fall apart and not cope...how he deals with that is his problem, and not your responsibility.
My partner has come to be my rock, the first one I've ever had in my life. It's taken a couple of years for him to learn what I need, and we don't always get it right, but he does his best.
I wish the same for you. xxx