Don’t quit yet; require shared responsibility for failure, not just confidence it can support you both.

You want to build something together, but it must reliably support you both. You’re demanding shared responsibility for failure before defining the income threshold or what that responsibility means in practice.

If the business could support you both but your partner wouldn’t share blame if it failed, would you leave?
No; I need shared responsibility too.
What would make failure feel shared, not yours alone?
My partner would take equal responsibility if it failed.