Yes. I do this all the time, for unexpected splits and temporary holding while I build new hives, and sometimes for overwintering smaller hives (1.5 deep equivalent or less).
Three things to keep in mind:
1) Each hive must
have a separate entrance, preferably at opposite ends and/or facing in different directions.
2) You must
have solid divider(s) between them that separate the halves of the hive. Ideally a "follower board" that fits flush to the inside of the hive (less than 1/8" clearance).
If that is not possible, less perfectly fitting follower(s) and a multi-bar honey barrier on each side should keep the queens from hunting each other down and reduce drifting.
***If you do not manage both of these things, you will end up with just one big hive within a few days.
3) Except in the most carefully managed of hives, this is a temporary
solution. Eventually they will get big enough that you can't keep them together in the space, or one or another queen will disappear. With a lot of care and being ok with losing the occasional queen, we have done this for up to 5 months at a time. You are still going to have to convince your wife eventually.