Your ex is not her parent, but you are. And you are divorced. Your FAFSA should reflect that you are divorced, along with the date of the divorce. The purpose of the question is to determine whether you should include a spouse’s income. The date is important, since you could have been married in the base year used for FAFSA even though you are not married at the time you filled out the FAFSA - for example, if you filed taxes in 2019 as married filing jointly but are no longer married, you would be able to separate out your own income from the joint filing for FAFSA purposes.