Everyone in the Arc only had one wife. Abraham was content with Sarah while she was alive ... when she got old and noticed she was 'sterile', she tossed her haindmaid to him so he wouldn't have to leave his stuff to a servant. After being tricked by Laban, Leah & Rachel, well, that was simply a catfighty 'one-upper.' They were tossing handmaidens right and left at Jacob. [Probably why in the Law Code marrying two sisters was forbidden.] Isaac only had Rebecca.
At other times, in the Bible, one would under obligation marry the wife of their dead childless brother so as to not let his house & inheritance die out.
Solomon well I recall reading somewhere where his concubines and various wives were displeasing to God.
But yeah, ancients had multiple wives and they also had constant wars going on depleting the male populace.