You and your ex can’t do it separately. That’s not how it works. It’s integrated.
Your husband’s income counts because his income contributes to the household expenses. Without his income, you would have more need. For example, if you and your husband each make $100k, your household has $200k available to pay the mortgage/rent, insurance, food, transportation, etc. I guess you can view them as fixed expenses that would exist whether or not you were married. If you were not married to him, you would only have $100k available to pay all of those expenses, ergo more need.