there is statue for State where you live which deals with how long a CA or any creditor can file suit.
check with your state to see if anything has changed.
As far as CRA, they go by FCRA......baddies fall of in 7 years.
here is a whole thread full of info.
keep a close eye on your report. You never know what a CA will do. If it appears on your report you can DV them and dispute it with CRA.
If the account was only in ex-hubby name they are just trying to get money & you are not responsable.
If you were an AU it still is not for you to pay.
With the SOL past in your state I would just ignore the letter.