I, personally would want to live with someone first for at least a year to find out if I can deal with all his quirks. If not, then hes out. The townhouse/condo will be mine, so he would have to leave. I think that you really find out a lot about a person once you live with them, things that you don't see when they go home. Like do they throw their clothes all over the floor after they take them off, do they keep a tidy bed, is their room clean all the time or messy, noises they make when brushing their teeth, do they go commando all the time or just around you?
I think that most marriages fail because the couples don't really know each other and living together first is a way to decrease the chances of divorce later on. IMO.
ETA: I meant to put in here that there must be a ring on my finger in order for any of the above to be valid!
Q