Considering, ~50% of marriages end in divorce, its pretty much coin flip odds.
With that said, I have always viewed marriage as a positive and consider myself happily married. Its worth the roll of the dice. You are right though, its important to invest the time to ensure you have the right partner. I was with my future wife for 6 years, owned a home together and shared a bank account before we got engaged. There were no surprises left by the time we got married.