I quit my well paid job to start my own business. I used to want to do whatever it takes to make it work. All went well 'til recently – backstabbing & disrespectful co-founders, lack of confidence, burnouts, I feel worse than ever, time to quit?

Maybe. All startups go through really rough periods. If you no longer trust the people you work with it's OK to quit.

Burnout is very common for entrepreneurs. Suggest you take some time off to recharge. Suggest reading Entrpreneur's guide to keeping your shit together.

I am a single founder and i had the same with employees that were jealous on my success. I had to fire most of them.

As long as we work together with other people, which is also a gift, jealousy etc. are normal parts of the business. Get rid of negative people surrounding you.

It is not uncommon to be there. I had the same from a co-founder when he sort of tried to push me out; although I am the founder and I put double the effort he did. I had considered it for a second - to quit - but I quickly realised how would it feel like quitting something I really love and believe in, especially after that effort I have put in. So I came back the next day stronger, acting like that this is me and this is my startup that I started myself, dealing with him very formally for a year. I increased that amount of effort and took on every opportunity to publicly represent the startup. Later he felt smaller and smaller as work increased until one day - a year from that incident - we raised funding and he could not put in cash so we asked him to quit and he did. We paid him for his time as a kind gesture