You shouldn't demand money from your partner.
Thomas notices that his fiancé makes quite a bit more money than he does, and he feels resentful that the household bills are split evenly.
Thomas wants his fiancé to accept more of the responsibility for paying that household bills.
Thomas talks with her and explains that he would like to save more money, and asks if she could help by paying a larger share of the bills.
Thomas insists that she immediately begin contributing more toward the monthly expenses.
Both parties feel respected, and they come to a financial arrangement that will be best for the entire household.
She feels as though she is being unfairly attacked and builds a sense of resentment, while Thomas feels badly for lashing out at her.