Many newly-married women still opt to take their husband's surnames after tying the knot. But what happens when everything goes sideways, the marriage ends in divorce and the guy's former wife wants to keep his name? What happens in Ontario when that's not what the man wants? A man can negotiate the desire as part of the divorce settlement.
Some women, especially those who have been married for years, may be known by their married names. Perhaps everyone knows her by her married name. Perhaps some women just don't want to go through the legalities of changing their surnames back to their maiden names. But if it makes her former husband uncomfortable, it may make things easier overall for the divorce process if she changes it back.
In any case, a man who is uncomfortable with his former wife keeping his family name should say so and discuss this with her before the divorce becomes final. The bottom line is, however, that a man's former wife who took his surname at the time she married him has every legal right to keep that name if they divorce. So, if talking about it doesn't help nor offering more by way of a monetary settlement doesn't help, there really is nothing a man can do about it. In the rare instances when a husband takes his wife's surname, the same applies.
Divorce comes with its own set of rules in Ontario. They can often be confounding. A lawyer may be able to help enlighten divorcing clients on what seems to be gray areas when it comes to separation and divorce.