My biggest mistake as a startup founder

Separating your identity from your business is important. Mixing the two up is a recipe for disaster, as you found out. Sorry to hear things didn't work out, you seem like a cool guy. I'm sure your next startup will fly now you've learned that you don't need to have a successful business to feel worthy.

There's always up- and downsides. In a few years he'll realize that this failure led to a massive personal growth of personality and character. He'll see that it saved him from decades going on acting like a huge d*** and layed the foundation for deeper and more personal relationships in his life.

Yup! I'm sure many founders who have come before you have thought the same way. It's easy to look for validation in the wrong place. Thanks for sharing. I'm sure this will help others.