That is relative. The situation for a woman who has been a SAHM for years is not the same as it is for someone who has been working that time. When you go looking for a job, experience and contacts are important to get a good wage. That means that economically, the person with better CV, has an advantage.

The counterpart is that the SAHM has more experience taking care of the children. So, basically, when they get custody, it is an acknowledge that they have more experience at that (unpaid) job. And many times men just need to ask for custody to get joint custody. SAHM can start a career, but if you have no work experience and are older, you start with a disadvantage.

Also, having sources of income is helpful in a divorce. The thing is that many times women are tasked with the unpaid work. As a single parent, you would probably are at a disadvantage with coworkers who have someone to do those things for them when competing for promotions. That is similar. Sometimes those things need to be said.

Also, not cleaning the house when you have children has consequences. For example, it is an unhealthy environment for children. Sometimes choices are loaded.

But sure, getting a divorce or stop doing chores is an option. Only consequences aren't the same. In the same way that a man suffer more judment if he doesn't have an income, a women who has a dirty house is going to be judged (and pay a higher price).

In some ways it is like the two sides of a coin. Women get custody because it is assumed they are the ones doing the caring. But at the same time, if they don't do the caring and the cleaning, they are punished harshly. Men are assumed to get an income and if not, they are socially punished.