Yes, some men get jealous over their mistress, but this does not always mean the married man loves the mistress, but some men feel she is their property and in only a very few cases is it truly love. Remember, this married man has a wife and he would be jealous if his wife had another man on the string. Mistresses often lose when a wife is involved and if the cheating man really cared about the affair she would not be his mistress; he would get a divorce and either live with her or marry her.