My recommendation is to make a list of everything in your life to which the Fatal Flaw Theory may even remotely apply, where your return on your financial or emotional investment far exceeds expectations.
This is an exercise in realism, not pessimism. As you review this list, ask yourself if you have really done your due diligence? This will force you to make some honest revelations or underscore your vigilance.
It also serves a way to condition you to act more responsibly towards yourself.