What is the nature of a partnership? I see the partnership of marriage as a braid-- one piece holds the other in place. Remove one and the whole thing unravels. So each piece needs the other to function; the parts cannot create a whole without this mutual knowledge and help.
If one partner is disabled or unavailable in some way, the other ought to be able to step in without request or instruction. Your cannot require of one partner the burden of knowledge while not accepting your equal responsibility to maintain that knowledge. Correspondingly, each partner must allow the other to create functionality in their own way. This means not only letting your partner achieve an outcome on their own, but also that you cannot insist that someone tell you how to do something.
The need for your partner to "be there for you" is primal, and I think for parents born of the knowledge that you will die and leave your children. Even as the parent of an adult I fear the idea of my children's lives without me. It is very hard to live without your parents, although it is everyone's fate. If my partner is not there for me, will he be there for my children? If my children and my partner don't understand how I do things, how will they learn to do things for themselves?