Depends upon the mormon and also where they live. Here in the USA, LDS can only have one legal wife at a time. If they divorce or the wife dies, they can get another just like anyone else. As an aside, a divorced woman cannot "unseal" herself from her ex-spouse without a fight. The mormon man, however, can "unseal" himself from any of his wives--ex or not--at any time. The FLDS, a branch of mormonism, practices polygamy just under the legal radar, having as many wives as they wish.
In addition, in countries where polygamy is legal (http://legal.blurtit.com/3423000/in-which-countries-is-polygamy-still-legal), mormons citizens can have PLENTY of wives. They still must live under the individual constraints of those country's polygamy laws, however. (Not by their mormon god's, who has forgotten vastly more than he remembers having.) In some of the listed countries only those of their national religion (mostly muslim) are allowed to practice polygamy. Not mormons. Which is why there are few to no mormons in those countries.
Don't be fooled. There are mormons who have actually moved to countries where polygamy is legal, with their church's blessing as they did with those fleeing to Mexico and Canada in the late 1800's, just so they won't get out of... practice. Somebody's got to remember "how to" when the LDS returns to it once again. Because that's precisely what they intend to do the day after bringing the entire world under their cult religion's control.
And, by the historical way.... it was not 1890 when LDS stopped practicing polygamy, despite laws enacted to cease. It took yet another, more strict law in 1904 known as the Second Manifesto, to get them to finally stop. Reason being, despite the first manifesto, it was discovered that, despite their promises, some of the highest LDS leaders had been thumbing their noses at US law all along, taking new wives ad lib.
"A man who is not satisfied with one woman and seeks out other women is on the path to decline".
---Parabhava Sutta [Buddhist scripture]
A 2012 study from U of British Columbia shows that, in polygamist cultures, "the intra-sexual competition that occurs [in polygamy] causes greater levels of crime, violence, poverty and gender inequality than in societies that institutionalize and practice monogamous marriage."
--Science Daily, 24 January 2012.
· 5 years ago