Something I’ve found helpful: imagine you were starting from scratch today. Is this still THE problem you would want to work on? If not, move on. You’re right that 6 mo is not a lot in the grand scheme of things. Sunk costs suck, but there’s no getting them back.

If it’s still a good problem, then maybe your cofounder is right and the solution you were working on won’t solve it. If he’s the tech guy and you’re the business guy, I would assume you’ve done more of the talking to customers, but maybe there’s a tech challenge he sees. Worth investigating.

Strongly suggest against getting wrapped up in cofounder conflicts - that definitely doesn’t solve a problem.

If this is THE problem you want to work on, and you think your solution was headed in the right direction, modern no-code tools like Bubble make developing an MVP doable for a nontechnical founder. Depending on exactly what you’re building, something even simpler like a newsletter or some Google Forms integrations can do it.