Why would Bertie conceal his salary when it was a matter of public record?

I have been mystified for some time by one aspect of the Bertiegate affair. Time after time, I have heard otherwise sensible people say something to the effect that perhaps Bertie's holding £50,000 in cash back in the 1990s's might have had something to do with his then ongoing separation from his wife. I have heard Pat Carey say this on the Vincent Browne Show and I recall Vincent Browne saying something similar on another occasion.