On the hook for ex's debt?

My ex-husband consolidated his student loans shortly after we married in 1996. The consolidation was through Sallie Mae. We divorced in 2003. As far as I know, he still has the loan.
My concern is that if he were to default, Sallie Mae would try to seek payment from me. The best that I can remember, I did NOT sign the consolidation loan but we did live in a community property state (Washington) at the time. None of the loans show up on my credit reports.
My question is how do I know for sure that I'm not on the hook for his debt? I can't ask him to produce the paperwork. Do I call Sallie Mae and give them my SSN and ask whether they have me listed as liable for anything?

With student loans, the only thing that matters is whose signature is on the pro note. If you were not on it, you have no liability.

If my memory is faulty and I did sign something, would it for sure show up on my credit report?

Did you take out any student loans yourself? You can try logging into NSLDS and see if you have anything there. This will only show federal loans. If you had private loans, it wont.