Can I seek payment from my ex-husband's estate for payment of his debt?

Question Details:

My ex-husband passed away nearly 1 year ago. He stated in our separation agreement, filed with the court, the he would transfer our joint credit card into his name and pay it off (strictly his debt), and that he wished me to be the beneficiary of his life insurance policy. Unfortunately, he passed away just 3 weeks after the divorce was finalized from a heart attack and was not able to complete the paperwork for these things. His mother (prior listed beneficiary) took the life insurance money and I have been paying off his debt for the past year. Do I have a case? Is there a SOL? Important Notice