It’s more like “try to not BOTH lose your shit at the same time.”

If one partner feels they truly can’t experience illness because another partner needs them to do all the emotional heavy lifting, they will either (A) leave, or (B) burnout, and then leave.

My partner has OCD.

I have autism and anxiety.

By our powers combined, we make for an excellent supervillian.

This is why IMO it is important to have a good level of self responsibility over your own life first before trying to get into a serious relationship. You may still be ill for the rest of your life but having some coping strategies, basic self care routines and such down first is essential. It is extremely unfair and toxic to always rely on a partner to bring that stuff. Its almost akin when men suddenly expect women to do all the housework once they get serious in a relationship. It should be a shared responsibility.

Im my experience relationships that start with a high level of codependance often burn out in a very painfull and destructive way, often setting both partners back significantly when it does break down.