I am not an attorney therefore I can not provide you with legal advise, just basic information on how a short sale works. The first thing to determine is the current value of the property, if it exceeds the amount owed on the home, then it would be a short sale. In order for you to have priority in getting paid, the mortgage you indicate you hold on the property should of been recorded prior to the equity line that your ex obtained. If your $90k mortgage was in fact recorded prior to the equity line, then your position is more favorable, and it would be more for the second lien holder to negotiate the terms of the short fall on the payment of their debt. This would be something that your ex and/or her realtor or real estate attorney would have to work out between you and the equity line lender. The strongest suggestion from me would be for you to seek the advise of a real estate attorney to ensure that your rights are properly protected with this transaction. Good luck and should you have any additional questions please feel free to contact me.
RE/MAX Advance Realty
Since you hold the first mortgage you could probably foreclose and take ownership and the Equity Line of Credit may accept a short payoff. Now if your Mortgage for $90k was NOT recorded on public records BEFORE the HELOC was recorded then you may just have lost $90k because your "first" will now be a 2nd and the HELOC a first mortgage. So contact a title company and/or attorney asap or view the public records online at the county clerk's office to make sure your mortgage was recorded BEFORE the HELOC!
All the best,