What a load of rubbish. It's like placing a trade without a stop. You may have the best of intentions and genuinely believe that it will work out, but little is certain in life, and relationships are not one of those. People change, people's feelings change, and relationships change. What may be a perfect partner in the present may not be perfect down the road.
People always moan about society's slipping values. They've been moaning about it for thousands of years.
Edit, I see you have been married for 31 years. That's great, but many will never last. It isn't necessarily because they chose the wrong partner, and even if they did they probably could not have known.
You can't know someone completely, as we never know what anyone is capable of. Then throw in the fact that people can change. Stick it out and work through problems? Sorry for another trading analogy, but I think it's appropriate. If a trade starts going downhill, you cut your losses and learn from the experience. You don't hang in there hoping that it turns around, because it could get very messy.