Entrepreneurship is a journey of self discovery. A journey in which you do a lot of introspection and self-discussion. A journey where you talk to yourself. A lot.
When you talk to yourself, you talk about anything and everything. Talk about things, which are very personal. About things, which do not fit in the normal world. Things which you cannot discuss with anyone you know.
Similarly, as an entrepreneur, when you are hit by a thought, which you think might sound absurd to others, you keep it to yourself. You do not discuss it with anyone and scrap it instantly. Or you try to give it some shape before discussing it with someone, thereby losing its originality in the process. And lose a brilliant idea, maybe.
This is where steps-in the co-founder. This is one person in your business with who you can discuss every thought about the business before scrapping it. If you have a co-founder with who you can discuss any thought about your startup without any hesitation then you guys are already on the list of unicorns or will surely get there someday.
Every great company was born out of one such "absurd" idea.
If you do not have such a co-founder then you might as well consider splitting up and forming two separate companies. The two companies would complement and support each other on the core idea while having separate books of accounts.
This is your journey. Do it with yourself.
If you’re planning to start out and don’t know such a person then stop looking. You won’t find one.
Look for collaborator(s). Not co-founder(s).