He can get away with it now---but if he decides to run, there will be questions about her absence.
I don't think anyone can get nominated by either party unless their spouse is constantly beside them playing the supportive spouse. Look at what happened to Howie Dean, his wife never showed up and he went from being the supposed front-runner to last place almost immediately. sKerry's wife/benefactor (or whatever the hell she is) also hurt him by opening her mouth. They need to stand there, smile, wave and every so often give a "canned" speech.