Monday's hot topics - Co-habitation

A question was posed on the forum:

Is co-habitation against the bible?

That is a tough question considering the implied promiscuity involved in today's culture. Some have posted saying co-habitation is allowed in some circumstances, like when Elijah lived with a widow. Others take a hard stance and say that we should be beyond reproach and never be in this situation. I've personally known friends who lived together before they were married and claim 'nothing happened'. What do you think? Post your thoughts here on the forum!