This.
You either believe in the idea enough to get it traction or start your new one.
Don't try to do both.
You either believe in the idea enough to get it traction or start your new one.
Don't try to do both.
It's amazing how as humans we cling to the slightest thread of hope.
Wish your co-founder the very best of luck, sign everything over to her, and walk away. Hope she does amazingly well and can fund your 4th or 5th startup because you're still friends.
It's all or nothing pre-traction.