I was addressing your reference to heterosexual couples. Not having a ceremony is not big deal. It's naive to think that only having a civil registration of some kind will avoid the trouble and expense of divorce. If 2 people have granted each other the mutual rights that have been mentioned in this thread, separation will involve trouble and expense. Mutual purchases (especially houses) need to be divided, responsibility for debts needs to be clarified.

This is why I often wonder why people live together for long periods of time without marrying. They seem to think separating would be easier in some way. It seems to me it seldom is.