Splitting domestic labor when one partner has a more demanding/higher paying job?

Hi all! My fiance and I have lived together for three years. In that time, I’ve had a higher-paying desk job with a short commute, while she had a lower-paying standing job with a longer commute. I paid more of our expenses and took on most of the domestic labor (cleaning, groceries, pet care, etc). It made sense for our lives, and I was happy to do so.

However, our roles have just switched: my fiance has a new job with fewer hours and a shorter commute, while my job has gotten more intense, with more travel and longer in the office.

When we get married, our money will be OUR money, and we’ll stop counting who pays for what. But I’d like to figure out a fairer split for our domestic labor. Recently it’s been challenging mentally to be doing most of the chores while also working longer hours and providing more income / insurance.

Have you been in this situation? How did you approach it? Obviously I’ll talk with her first, but I want to get a sense of how other couples do it.