I am personally very against polygyny (the practice of having more than one wife) except in Islamic cases.
OPNO girls in total support Islamic polygyny when the following is done:
The consequent wife/wives are a "Shariah law defined orphan". This is, a woman without any surviving Muslim male "maharam" family members capable of financially supporting her. This can fall to widows, divorcees, and those who've suffered the tragic loss of all living relatives. The Qu'ran states that the purpose of the condition of being allowed to marry more than one IS TO SUPPORT THIS GROUP OF WOMEN. Not for any other reason.
Next, the husband must treat all his wives and their existing and possible children FAIRLY financially, physically, and with all he says. That means they are given equal time out of his day, equal nights, equal provision, and he can't say anything emotionally to one and not to another. This is very hard for a man. Almost impossible. It can be done, but most men can't.
If there is a saving required for housing, the first wife gets to save first, then after that, the second, after that, the third, if they should so agree.
*Any of the wives can choose to give up their rights in things should they wish to, such as for sex, or a day, or for something like money that the other wives have, but unless they wish to, Islamically, their husband has to give them same as the other women in his life*
Also, to meet the conditions of fairness, there can be no negotiating for a second or third ect wife in secret, or marriage in secret. How can a man afford equal time to his first wife if he's with his second wife and she thinks he's spending the night with his buddies? Also, announcement of the marriage is a shariah requirement to make it legal. If he is talking to another woman without the first wife knowing, even about marriage, it is cheating if she doesn't know. Not allowed.
Also, the first wife needs to know, because if she doesn't agree, she DOES have the Islamic right to divorce and what she negotiated for in terms of her marriage agreement and her children as agreed upon before she married. If her husband takes on an additional wife he may not have the financial ability to meet her divorce terms if she specified them in her nikah/melka contract.
*In Shariah law, a woman cannot specify that her husband not take a second or other wives but she can ask for divorce and compensation on the event that he does, before marriage to any man*
Contrary to popular belief, a man is not given permission to remarry just ANYONE he fancies by the Qu'ran even IF his wife is sick or cannot have children.
The example given by the Prophet Mohammed would tell you this. He had only ONE wife who was a previously unmarried virgin who he got engaged to before he married any other and she herself could not give him any living children. He did not marry another woman except those who were what shariah-law considers orphans (widows, divorcees) and that his wife could not conceive any children was not an excuse for lifting the Islamic burden of marrying a Shariah orphan on the permission of marrying additional women.
Although the first wife MAY give her husband permission to marry as he chooses instead of the Islamic burden of marrying a Shariah orphan when she can't have children these days, there is no Islamic pretext and example that this may even be permissiable from all I have personally studied.
For the wife who is sick and the husband wishes to remarry while she is sick? Even if she is comatose he STILL has to spend equal time with her as his next wife.
MOP's father remarried while his first wife was sick. She didn't even know he was there, but he still dedicated 50% of his time with her, caring for her, and just being there.
In Islam you aren't allowed to date, and divorcing a sick woman is a little cruel, so anyone who would look down on the man for what he did, needing a wife to love and have companionship but unwilling to leave the wife who'd stood by him for years, I can't understand.
There are more rules even than this, but knowing this, if you know of Omanis in a polygynous marriage, and they are unhappy, odds are they didn't meet any of the above requirements for their marriage so in alot of Islamic opinions, the husband didn't even care to make his marriages Islamically valid.
I stand to support Islamic multiple marriages even though I know the majority abuse the institution, as I do know some cases they are warranted, and some happy women (albeit with husband's who have no personal time whatsoever).