I understand why you'd say that, but I feel the opposite. I think divorce strengthens marriage as an institution, because it helps to ensure that the people who are married are people who are genuinely committed to their union and WANT to be married. Granted, it's not perfect, and lots of unhappily married folks still trudge away without getting divorced, but I think divorce helps rather than hinders.
The assumption that one can just divorce if anything goes wrong or if you're bored or whatever hardly strengthens marriage. People who do not believe in divorce are more likely to attempt to work out problems, rather than divorce for bullshite reasons like "differences in temperament".