Was there ever actually a society that tolerated exactly two wives, but no more?)

Ok, so you made me curious and I'm sick in bed, so i looked up the next bit.

Several societies have historically allowed exactly two spouses:

Customary “two-wife” limits in some precolonial and early colonial West and Central Africa, e.g. among some Akan and Yoruba groups, a second wife might be permitted only if the first wife was infertile or agreed to it.

Some Polynesian island societies (such as in Tahiti and Hawaii before European contact) sometimes allowed a man or woman to have two recognised partners — for example, a formal spouse and a secondary “companion” or “ritual partner.”

In the Arabian Peninsula, before and just after Islam’s emergence, some tribes effectively tolerated “two wives, but no more" before Islam later codified up to four wives

In Tibetan and Nepali societies practising fraternal polyandry, a woman might have two husbands, typically brothers, a practical arrangement to prevent land fragmentation

I've heard variation on Aboriginal Australian social structures having two partners, but that's one for the first part of your adult life, another for later.