Let's say I marry a woman and she wants to have a career instead of doing all the housework, cooking, and childrearing and stuff. In that case, it's only fair that we split the expenses (e.g. rent, clothing, food, utilities, savings, household supplies) 50/50, and whatever is left over should be for personal spending on hobbies, vidyah games, or whatever.

It's only fair. My wife shouldn't be able to freeload off my income while she pursues her low-paying self-actualizing career. I should be able to enjoy the fruits of my hard-earned money and spend it on my own hobbies and interests. If she wants to spend money on herself she better earn it.