Shouldn't you wait until you get tenure first ? Doing it immediately beforehand seems like peculiar timing.
I think the timing of a competing offer right now trumps other considerations.
I assume the OP is looking for a spousal hire with tenure. If so, we're talking about some pretty heavy lifting, which requires considereable leverage. At the moment, OP does not have tenure, is about to come up for tenure, which is one of the most vulnerable times in one's career. The OP may require more leverage to negotiate a spousal hire with tenure than he/she has at the moment.
It also depends how the offer was obtained. It may very well be a standing offer.