You are both right to a degree. As PQ said it depends on who you are married to and how you yourself are as a spouse and person, and how strong your love and commitments are, that will determine if your marriage can survive traumatic trials or not.
Again I think of my parents. They were married for nearly 30 years, but stayed unhappily together solely for the sake of us kids. So the moment I married and had my daughter(I was the last one of my siblings to get married) my mom called it quits, and divorced my dad. Though many people, including the judge, tried to convince her to do otherwise, she was determined not to spend the rest of her life married to the man she didn't love anymore(mind you, their's was a love marriage).
An aunt of mine on the other hand, though she married purely to please her parents to a man she didn't really love, the death of their child and monetary difficulties, actually strengthened their relationship and the two of them are still together in much better times now.
Truly marriages, that depend largely on changing human emotions, are unpredictable.