I think the best advice I have heard on this subject is that you shouldn't try to keep tabs on who does what in an attempt to make the relationship 50/50. If you try to keep track of stuff like this as "percentages", then you are constantly comparing who does what and the other person can ALWAYS do more. Instead, people should put in as much effort as they can. You should think that you should be putting in 80% of the effort. That's for both men and women. I think people who are early in their relationships do this naturally. When you start "comparing", then the relationship becomes "transactional", your partner comes up short and this directly leads to unhappiness which directly translates into divorce. I have no doubt this is responsible for many divorces. It's not cheating, not abuse, not finances - ultimately it is about who does the dishes. This may help to explain the other question I have about why women divorce their perfectly good husbands in such high numbers.

https://franklinwuhoo.medium.com/the-bill-and-melinda-gates-divorce-just-another-in-the-flood-of-divorce-initiated-by-women-b02cd4ceca03

I would say this is about happiness which is directly related to expectations. Is this a reasonable expectation?