Folks,
I agree that Jeff did a very selfish thing. And that’s no way to run a marriage.
But nobody here except the OP has the rest of the story. or more importantly, the preceding episodes of the story.
We have no idea if he’s normally reasonable and she’s a raging tightwad, or OTOH, if she’s normally reasonable and he’s a raging spendthrift.
Asserting that one or the other has mental problems is silly, little more than high-falutin’ name calling. “Neener neener neener, you’re a psycho! And I’m not.” That’s not helpful.
I think it IS clear that they have incompatible approaches to money, or at the very least they have a major communications problem about money. And that MUST be solved soon or it’ll really tear up the marriage.
The statistics seem to say that most marriages fail over one of three issues: money, inlaws, or having kids.
We know these folks have one issue already. Do they perhaps also have the 3rd?
Did Jeff spend the money as a (poorly chosen) way to force the issue: “See honey, we can’t afford a baby now”, when what he really means is: “There’s no way I want a baby; certainly not now and maybe not ever?”
We here don’t know, and it seems silly or at least unhelpful to focus on how wrong Jeff is/was or how to “punish” him.
Marriages don’t operate on punishment, because neither will accept the idea that the other has the right to mete it out. And really, they don’t have that right.
Bottom line, these two need to talk A LOT, and without anger. That may not be possible for a coupe of weeks. The truck is almost certainly a symptom rather than the disease. They have got to get to the disease in their relationship, whatever that is.
Either that, or they’ll sabotage each other in a tit-for-tat struggle to their own emotional and perhaps financial death.