I get the impression that you two had some sort of semblance of a 'thing' going on, recently.
This was not long ago.
I can't imagine someone insulting another sexually for an encounter that happened LONG ago.
A small dikk that stayed in the back of your mind through courting, engagement and marriage?
Don't sound right.
Then, adding his nonchalant responses - it seems as if he fukked her, then kind of ignored her/bushed her, then came back out of the blue trying to get some snatch again. She felt a certain way about being treated like that and decided to cut him off with a zinger.
Sadly, most married women will entertain dudes on the side. In their minds, the war has been won - it's over.... now what to do with all this boredom and time.