The Bureau of Vital Statistics in Austin, Texas keeps track of all family law cases. I often have people call me to see if they are legally divorced.
1. Check the person's social security number. If the person is dead then the social security number will be inactive. And, you don't need a divorce since you are a widow.
2. If #1 does not work, then go to the Bureau of Vital Statistics website and search for information. With your full legal name, date of birth and social security number your info should show up. To be on the safe side, also include info on your spouse along with their date of birth and social security number (if known). Many times, the spouse will not include your name correctly or your info correctly to make it hard to find you.
3. You can also hire a private investigator to do a search for you. This tends to be fairly expensive but perhaps it's worth it to you.