The Indiana web site on pre-1850 marriages shows this for Nancy Demaree:
Last Name: DEMAREE
First Name: NANCY
Spouse- Last Name: MAY
Spouse- First Name: SAMUEL
County: Ripley
Date: 12-28-1850
Remarks:
It's after the marriage you are looking for, so it could be that Dudley
Johns on died within two years of his marriage to Nancy. The marriage to Dudley
Johnson is not shown on the Indiana records, however. Only her marriage to
May in 1850.
Alan McCullough