Mason chose to let her see his white shirt in this condition. What was he trying to tell her?

Was he hinting at her that he was starting to not take their marriage seriously? Or, was he trying to assert his freedom?

In any case, she chose to ignore it. Rinsing the white shirt, she put some detergent on it and started to rub and wash it. As she cleaned the shirt, the smell of perfume and the lipstick were gone as well, as if nothing happened last night.

The white shirt looked as good as new.