Perspective is in the wrong place. Don't think in terms of relative value: 'I'm doing 80% of the work and getting 50% of the benefit'. Instead think of the absolute value of a co-founder: 'Solo I might be able to make an acquihire for a good signing bonus, but as a team we have a shot at eight figures'. Half of 10mil is better than all of 100k. If the co-founder doesn't increase the expected value of the company, then you're correct to pull the plug

Secondly you have a narrow criteria. It's extremely difficult to find people who can continuously work at a high volume. Consistent 60-80 weeks just aren't in the realm of most people. It's not incorrect to want this, or to search for it, just don't expect to find it regularly. Even when you do find someone like that, you may not realize it. Visibility can be a huge impediment. You'll directly see 100% of the things you work on and accomplish. Maybe 10-15% of what your co-founder works on.