If you believe in arranged marriages, you'll stay together even if you fall out of love because you don't believe it is necessary for the marriage. Too many Westerners mistake the calm, boring life as falling out of love and think the marriage is over, because they assume that hard hormonal rush when you are dating is supposed to last a lifetime.
They also see relationships as more disposable, so they don't struggle to work through challenges like a family member's illness or job loss or financial problems.
The US divorce rate is NOT 50%, per Shaunti Feldhan's research. There was one point in the 1970s when the divorce rate hit half the marriage rate, but marriage rates are back up while divorce rates are down. 70% of first marriages last the lifetime of one partner, 50% of second marriages last the lifetime of one partner.
However, if you just live together without marriage, 3/4 of those unions break up within 10 years even if you have children.