Jennie,
The 1830s are before the start of statutory marriage registration and so you will be dependent on church records to find the marriage. Do you know what denomination the family were? In particular, the bride, as it was traditional to marry in her church.
I note you say that Thomas Martin was in Griffiths but dead by November 1864. The Revaluation records (which continue Griffiths forward) show that Thomas Martin remaining as tenant of plot 14 in Corbally until 1876 when he was succeeded by John Hughes. Griffiths clerks sometimes didn?t pick changes of tenant for a couple of years but in general the evidence suggests that this Thomas Martin was still alive until c 1876.
If it is your family, you may have noticed a John Martin nearby in am agricultural labourers cottage (plot 8b). He could well be a relative. He remained listed until 1901 (though he is not in the 1901 census).
http://applications.proni.gov.uk/dcal_proni_val12b/ImageResult.aspx
I looked for a death for Thomas Martin from 1864 to 1878, registered in Omagh (which includes Corbally) but none is listed. He either died before 1864 or elsewhere in Ireland. No record of a probated will for him 1858 ? 1878.
What was Thomas Martin?s occupation? Do you know?
Elwyn