[Ronin]

At a guess? He took her to a restaurant to announce he was getting a divorce. She figured it was coming and decided on the plan beforehand. Hell hath no fury, etc.

At a further guess, there is a disappointed wanna-be young trophy wife out there somewhere.

[2ndDivisionVet]

Every woman I ever dated in the South had a gun in her purse, without exception. She probably didn’t have to plan anything.

[Bigg Red]

I think your scenario is probably correct.