This is the primary meaning I take the term ‘square up’ to mean. When I read the OP saying “I Love My Wife but sometimes I want to square up.”, though the meaning doesn’t quite fit, I took it as “I love my wife but sometimes I want to trade up”. Meaning, trade her in for a newer model, maybe with easier handling.
Sounds weird to me. Maybe it started as one of those, ____ do it in the ___ sayings. Or it originally had a carpenter’s square on it and that part got dropped? A visual pun in other words.
Googling it though, led me down a rabbit hole. “I love my wife’s butt…” - OK, I get that but, “I love my wife, my country and getting pegged” (complete with an American Flag and a bald eagle, left me a little confused.
It is, however, something Millennials and Gen Z have taken notice of in recent years - a lot of Boomer jokes, both amateur and from professional comedians, seem to revolve around older men hating their wives to the point where we wonder if they even wanted to get married in the first place.
Just google “Boomer humor” or “wife bad” and you’ll find plenty of examples.
I always thought it (I hate my wife humor) stemmed from the wish of men to be ‘free’ of their aging nagging wives who may have gained weight, don’t want sex any more, and aren’t ‘hot’ any more. Accounting for their deep envy and respect of Hugh Hefner and Playboy, where there are no old harrridans in curlers and ratty robes but an endless supply of ‘hot’ new better looking meat. And there they are, stuck mowing the lawn, stuck with their boring old spouses and obnoxious demanding kids.
Us tweeners were taught that. First with Ralph Kramden, then his “son” Fred Flintstone. Husbands were always afraid of getting bonked on the head with a rolling pin. Taught me everything I know about relationships.
I’m not sure where the line is between this, and more generally all humor involving complaining about or expressing animosity towards one’s spouse (or significant other), which is probably as old as marriage and/or humor itself.