I dont think its a good thing to stay with your life partner before marriage, you might loose all the freedom in your life. I would never wish to stay with my bf before marriage, who knows what might come up. I am a type of girl who cannot stand any kind of mishaps in my daily routine life. I am a social kind of girl and I dont want any one dominate my life and have restrictions in my way of living.
Well, I want to live together with my love, that's why I should married her. Marriage is about love and responsibility. For me, marriage is one proof for me and her that I love her. Where is the fun of marriage if you living together already. You want to be happy after marriage happened. Not only before and at times you married.
It is very good idea to try live together before marriage and to see each other every day. You will know him/her more deeply.