Equity line before marriage

My soon to be ex husband and I both signed a promisory note to a credit union in the amount of $20,000. (This money was to pay off his debts. I had never had reason to get any loan before as I do not carry much debt) I have copies of the promisory note.
This was established as an equity line of credit against my house that I owned before marriage.
When we separated there was a balance of approximately $17,000.00.
Now he refuses to pay any of this and has stated that he will NOT pay anything because it’s not his responsibility.
What can I do?
Because this was pre-marriage I was told that family court does not have jurisdiction.
I’m stuck paying this every month and it’s financially ruining me.
Can I sue him? If so, for what amount?
Thank you so much in advance for any help you may be able to offer.

Assuming the equity line was taken out during the marriage (between the date of marriage and date of separation), then your husband is also responsible for this debt.

Similar to assets, any debt acquired during the marriage and for a marital purpose are subject to being divided in equitable distribution. You would need to sue him for equitable distribution to have the court equitably divide all the marital property and debt.

If you took out the equity line prior to the marriage, then you are responsible for the repayment assuming the equity line is in your name.

Thanks,
This was PRE marriage and in both of our names.
Is there anything I can do since his name/signature is on the promissory note as well?

Since it was before the date of marriage and in both names, you are both responsible for it. He may be able to refinance it or take out a new loan to pay off the current debt, but there is nothing you can do to force him to do this.