1. Don't you want your man to officially commit to you? Why are you assuming he hasn't? My boyfriend and I have been together for 10 years and lived together for five. We have a home and a life together. We're officially committed, but marriage isn't for us. Now let's discuss the details of your spouse's commitment to you. Wait, why are you making that face? Oh sorry, am I being rude?
2. OMG, I'd never feel secure in a relationship without being married. Then you should definitely get married! Some couples enjoy partaking in an age-old social construct that they feel helps define their love and commitment. Some don't. Potato, potahto! I actually feel more secure in the knowledge that my boyfriend is with me solely because he wants to be (and vice versa), not because we've signed a form at City Hall and kissed in front of our great-aunts.