I really don't, but I assume it's true. Someone else once said that you can't find happiness outside [of yourself]. So being content is about finding inner peace?
I can't pretend to know your story. My story is not startup related. But "inner peace" frustrates me.
For my turmoils, it was about acceptance. Saying "Yeah... that happened" with the idea the past doesn't define me.
To make the past separate do something, anything, that "past you" wouldn't guess, even just once. Maybe put cupcake-sprinkles on your morning cappuccino or on a PB&J sandwich. Change your desktop wallpaper to unicorns and rainbows. Sing along to a death metal song before breakfast.
.
This does two things:
1. Bookends an era. The old era is now BSC.(Before SprinkledCoffee)
2. Means you can do things tomorrow that even you can't predict today.
Congrats. You are now living in a new era where even you can't foresee the possibilities.
No inner peace though. Your past will always be your past. You will continue to have feelings about it though it does get easier over time. Maybe see a therapist if you can.
I like Desiderata, one unequivocal phrase of which is:
"You are a child of the universe no less than the trees and the stars; you have a right to be here."