"A foolish consistency is the hobgoblin of little minds."
Honoring commitments is important, but so is adjusting to new information, even if it's only new information about your own productivity and mental state, or the revealed imbalance in critical-path-tasks and hourly commitments between partners.
OP may need more time away from the project, or may need more teammates with the right tech skills to help on current-bottlenecks.
Maybe knowing that 10 paying customers are lined up would help, as motivation and improved confidence in the partner's ability to equally contribute. (Maybe it's allow recruiting more technical help.) But maybe more people waiting for the completion would only add to the pressure and anxiety; he'll have to think about that.
I strongly suspect a major part of the problem is that OP has no peer technical help on the critical-path – all his partner can do is ask, "is it done yet?" That's a broken team.
Honoring commitments is important, but so is adjusting to new information, even if it's only new information about your own productivity and mental state, or the revealed imbalance in critical-path-tasks and hourly commitments between partners.
OP may need more time away from the project, or may need more teammates with the right tech skills to help on current-bottlenecks.
Maybe knowing that 10 paying customers are lined up would help, as motivation and improved confidence in the partner's ability to equally contribute. (Maybe it's allow recruiting more technical help.) But maybe more people waiting for the completion would only add to the pressure and anxiety; he'll have to think about that.
I strongly suspect a major part of the problem is that OP has no peer technical help on the critical-path – all his partner can do is ask, "is it done yet?" That's a broken team.