Good article. Prager says:
First, no matter what you think when living together, your relationship with your significant other changes the moment you marry. You have now made a commitment to each other as husband and wife in front of almost everyone significant in your life. You now see each other in a different and more serious light.
Second, words matter. They deeply affect us and others. Living with your "boyfriend" is not the same as living with your "husband." And living with your "girlfriend" or any other title you give her is not the same as making a home with your "wife." Likewise, when you introduce that person as your wife or husband to people, you are making a far more important statement of that person's role in your life than you are with any other title. (More)