I'll take those odds. 50/50 is what, 50 times better than any casino?
50% divorce rates happened because we got lazy, among other reasons. Way back in the day, when you got married, it took a literal act of god to get out of it alive. Husband beats you, you stay at mom's for a few days while he cools down and then she sends you back to him. If one partner cheated, you *might* be able to get an annullment or divorce. Basically, it really was a "ball and chain." Therefore you had much more incentive to get along.
Today, we have celebrities getting married while drunk and getting annullments the next morning. Divorce and remarriage is common and even accepted by the church to some extent. People regularly live together unmarried because they don't want a wedding yet, or want an easy out if things go sour. The whole attitude about relationships has changed drastically. Like everything in America, you no longer have to work at a relationship. If it doesn't blossom naturally, it's not worth having and you move on to the next person that makes you all starry-eyed.
This is wrong. Of course you're going to get into fights and not be in the mood for sex and catch yourself looking at other people. Life isn't perfect. But many times the relationship fails because both partners did not communicate with each other, or failed to compromise on an unimportant issue, or had totally unrealistic expectations for their partner, or couldn't keep their genitals in their pants for five minutes.
If you want a good marriage, act like you want a good marriage, and as long as you find someone else who also wants a good marriage you will probably do very well for yourselves. If you marry someone who is a drama queen (male or female) or play the part yourself it will likely fail.
My uncle has been married something like 6 times to 4 different women. That doesn't say anything about the institution of marriage so much as it says something about my uncle and aunts.