My girlfriend and are living together and we are having disagreements about how to split the cost of living for rent, utilities and general living expenses. She has an adult child who has graduated high school almost 2 years ago. He isn’t working, doesn’t contribute much around the house in the way of chores and doesn’t really associate when I am around.
The problem arises when we talk about finances, I make a little more than twice her income on a gross level.
What would the rule of thumb be for splitting costs so it works for everyone?
Should it not matter that he is of age and not working and we split only based on incomes?