I didn't find their marriage 1834-1836 at Early Rutherford County Marriages, www.tngenweb.org/rutherford/marr.htm
. However that is only an index and might not be accurate. I'd doublecheck with the Rutherford County Archives, www.rutherfordcountytn.gov/archives/index.htm
I continued to look for the family and it looks like Devorix died after the 1850 and before the 1860 Census in Dyer County.
Dyer County also has archives
PO Box 1360
C/O Clerk and Master
Dyersburg 38025 or 731-334-8185 or email email@example.com
You can check with them about death records and will/probate records. I don't know if his wife's maiden name will be in those or not.
I tried to find his wife's death info (shown as E. A. on Dyer Co. 1850 Census and M. E. on 1860 Census) but didn't find her after the 1860 Census and looked for Mary Williamson too. Successful Searching!