That's just about everyone.
You slave over relationships and infrastructure, only to find the universe doesn't want another product like yours (at least, not enough to pay for it).
So you accept the lesson and move on, sadder but wiser. Or you:
- Don blinders and blame the customers
- Get angry and blame the employees
- Get stoned before lunchtime
- Keep beating the dead horse
- All of the above
The best way to deal with them is to reconnect with your "why" (why did we start this venture in the first place?) and remind yourself of everything you accomplished along the road to failure.