Yes! If he is bold enough to cheat, where is the indecency in her for taking control of an unwanted invasion of her marriage, even her life? She is justified.That is her life and cheaters and invaders have no right to violate her. (If a thief breaks your door down, are you going to sit and do nothing or take action? You have a right to ward off invasions or threats to your life and your family's well being.) There are too many incurable diseases being passed around to sit and do nothing about something that could give a spouse a death sentence. Many spouses have regretted not taking action after contracting a disease that ended their lives. Cheating is crossing the line. It is a breach of a promise to be true. It is a defilement of marriage. When that happens, a spouse has a right to take action. Cheating is a very serious and dangerous offense that could upgrade to deadliness in more ways than one. Desperate mistreses or girlfriends have killed wives to get husbands. Cheating is devilish. Children, especially older ones, are often aware of a cheating parent, and they suffer silently. A cheater is very dense, irresponsible, selfish, and immature. Cheaters need to remain single or change completely.
"Once a cheater always a cheater" is not a fact. Some sincere people do change. Many surveys have shown spouses to indicate that they have cheated at least once in their marriages. Some people are ashamed and truly sorry for such an offence. Some stop it completely, even though this group may be a minority.