In Islam men can marry four times and they may keep all the wives at the same time. Women are allowed to marry only if they have been divorced by the former husband. If a woman divorces her husband or is divorced by him and then wants to reconcile later on she has to marry another man and get a divorce from him and only then can she marry the former husband. She is not allowed to marry more than one man at a time. If anyone deviates from these laws, they are punished according to the law of the land, which in most Islamic countries is in line with the Shariah or Islamic law.
In Islam How Many Wives Can A Man Have And Can He Keep Them All At The Same Time? Can Women Have As Many Husbands As Men Can Have Wives?
That is a great answer listed above. I would not think a woman could marry more than one man at the same time, it is only men who seem to be able to do that. Even though I don't agree with it, I think everyone should only be able to have one spouse. That is just my opinion though, I am not discrimination against it, I just don't believe in it.
Does a man need to take his wife's consent to marry another woman?