You appear to have both marriages in the same year but they were two years apart.
Iris Velinda BIRTLE married Wm Robt WEHSACK 1926
Iris Valinda BIRTLE married Jas Henry WATTS 1928
Below is a notice in the papers that may fit if wife had left him.
The Argus (Melbourne, Vic. : 1848 - 1956)(about) Previous issue Saturday 9 July 1927
I, W R Wehsack, of 8O Bridge rd , Richmond, will not be responsible for Debts contracted in my name without written authority.
Perhaps divorce might the step to investigate.
Did Iris have a daughter Shirley...see article below
The Courier-Mail (Brisbane, Qld. : 1933 - 1954)Thursday 21 March 1946
WOULD Iris Valinda Watts, of Port Melbourne, communicate Police Department, Brisbane, matter very urgent, daughter Shirley very ill. Everything else will be entirely forgotten.