Hello Miranhat, and I agree with Tony that it is nice to see everybody's experience/opinions, etc.
I personally think it's very difficult to have any hard and fast rules for this one. For example, I did not live with my first husband before we got married, and we are no longer together. My cousin, however, lived with a woman without marriage for over 20 years, and just got married last year because their grandkids (no kidding) kept bugging them to do it.
I think what is really important though, is that you and your Bf/mate/ whatever share the same values regarding this and other important life decisions. In other words, if you felt that you did not really want to live with a man before marriage, but he had no problem with it, and in fact thought it would be a good idea and a good way of getting to know each other before marriage...
or vice-versa, if you were cool with and in fact wanted to see if you were compatible before making a lifetime commitment, but he was rigid and pushing for marriage......
I think sharing these and other values are what is important, and I know for a fact in my case, the lack thereof is what ended my marriage.
Thanks again for the good thread and know you have support her at MUT whatever you decide!