Originally Posted by nycindie
I disagree that the "mono path" is the relationship ending, nor that meeting someone "better" is a major factor in mono relationships ending. Many times, situations like that can be an impetus for healing the relationship or marriage, because you see what's possible and start asking for it. Also - if, in a committed mono relationship, one meets someone else, compares them to their partner and is tempted to leave, there usually is trouble brewing in the relationship already. Another person didn't cause it.
Seeing that the average relationship lasts about ~7 months (at least from a few different sites I found) and marriage around ~7 years, why are all these mono relationships ending ? I know there is no "one answer" but a common thing you will find is someone "struggling" who finds a catalyst to break up when they meet someone new.
It seems very common that when a relationship ends at least one of the two people hopstep into another relationship almost immediately. The reason this occurs is because people generally don't like being alone and prefer to wait until they have alternatives before making large decisions. Humans generally prefer to be in poor relationships over being in no relationship.