How do we define this? What is meant when someone says 'living in sin'? Don't chrisitans sin all the time, in actuality don't we sin daily? I think most people use it to mean people living together, not married. But what is the difference between that and christians who do sin daily? Is it that as christians we can confess or sin and eb forgiven, but those living without marrieage are alwsy in their sin? Notice, this is not meant to be a debate on legal marriages, leagl licenses, or whatever.