My ex girlfriend stopped working to take care of our disabled child, and I help support her, and our kids.. How can I add her as my dependent?

Do you live together?  Did you live together ALL of 2024?  If not, you cannot claim her as a dependent.  

If you did and she made less than $5,050 for the entire year, and pay over half of her support you can add her as a dependent for the $500 Non Refundable Other Dependent Credit.  You will do this on the personal info page by selecting add a dependent. 

To claim someone as a Qualifying Relative, they must be:

• Your child ( including step children, adoptive children and foster children) or a descendent of them
• Your sibling (including half siblings) or a child of your sibling or a sibling-in-law
• Your parent or grandparents, including step parents and in laws
• Any other person that lived with you for the entire tax year
• Not a qualifying child of another taxpayer
• Someone that you provided over half of their support for during the tax year
• Has less than $5,050 in income (not counting social security)