My second husband had two women in his first marriage.
His wife and another woman.
It lasted about 2 years.
He says "Never again".
This is how he explained it:
(A) It was 2 against one ... he was always outvoted, and their household was female-dominated
(b) It was actually tiring trying to keep 2 women happy .. and either you struggled with who you slept with THAT night, OR 3 in a bed and no one got sleep even if no sex was happening ... resulting in tired, grouchy people.
(C) It was too much work to keep everyone happy. When you are in a 2-person relationship, there are 3 "entities" to please:
1) Me, 2) You, 3) Me+You
BUT he said when there are 3 people in a relationship, there are 7 "entities" to please:
1) Me, 2) You, 3) Them, 4) Me+You, 5) Me+Them, 6) You+Them, 7) Me+You+Them
He said it was emotionally exhausting.
And, my dear, if you don't keep EVERYONE happy, the household becomes a living h*ll.
Having two wives is one of those common fantasies that doesn't work out well in REALITY. It is best kept AS a fantasy.