u/Crazy-Environment-42

My ex Husband (39m) and myself (37f) finalized our divorce in December of 2025 after being married 18 years. We bought a home in 2015, but my credit score was low as a stay at home parent, so only his name went on the mortgage. In 2024, we got a heloc that does have my name on it. In the final divorce decree, we agreed that I would remain in the home until “at least May” and that we would both pay equal parts of the mortgage until “the sale of the home”. He is now telling me he will no longer pay his half of the mortgage and is demanding I either take on the entire mortgage (which I cannot afford) and house expenses, or move out (which I also cannot afford yet) and he will take over the home and associated costs.

My hypothetical question is if he were to stop paying his half of the mortgage, what actions would be appropriate to take? Will it hurt my credit if the payments aren’t made if my name isn’t on the mortgage itself? Also, I do not have access to the heloc, so I don’t know how I could make a payment either (I have reached out to the bank to gain access).

The kinship portion-
We have an apr (allocation of parental responsibilities) for my niece, and have since she was 2 years old, she is 8 now. We have not legally adopted her yet. Her bio-mom has been absent for 5+ years, proving abandonment. Her bio-dad, my brother, has been absent for 9 months. After 12 months, I would like to file for adoption. Neither pays support. My niece was not included in the divorce decree with my two other children because we haven’t legally adopted her. Although my ex was supporting her fully for the last 7 years, he is no longer supporting her and says if I want support, I should seek it from her bio-parents.

Outside of official adoption, is there any action I can take here to request support from him, as he has legal custody of her as well?

Location: Denver, Colorado