The 50% number is a myth. No one really tracks divorces in the US. That number was printed in a story in the 80s and continues to be used. Its nice and easy. You can google it and find many stories debunking it.
Even if it was correct it doesn't mean what most people think. It doesn't mean that 50% of couples divorce. It means 50% of marriages end in divorce. That number would include the large number of second marriages, third etc. The number of 30+ year marriages, in the US, is much large than people realize.
Brief tangent but divorce is the single greatest destructor of wealth in this country.
All the things that you mentioned impact the stability of relationships. The vast majority of married people that enter into "open" relationships are having other problems at home. The hope is that having other relationships will stabilize things. They rarely do. All your other problems will be reflected in the jealousy that will arise if one does better that the other. People rarely make a public announcement to family and friends that they have an open relationship.
Its the same with swinging. The people with good solid relationships can enjoy the change in partners. If you have problems it can be like pouring gasoline on a fire. I have seen and heard the meltdowns.
Posted By: YourMysteryDate
If marriage is the end goal and most relationships do not end in marriage then what makes open different than traditional in "success" rates?
If talking about open marriages...again, if something like 50% of them end in divorce anyway, why are we singling about openness as a relationship ending factor? Isn't money, kids, mismatched libidos, etc the cause of more relationships being ended than openness?