I would encourage you to look at product managers currently employed in your area by big co's. From those cohorts there might be some who are disenchanted with

I would encourage you to look at product managers currently employed in your area by big co's. From those cohorts there might be some who are disenchanted with the cube life and looking for a change. Especially if the big co might have people who possess domain expertise in the area you're building in. I'd also encourage you to seek out startup meetups or any programming that's done by people in the entrepreneurial ecosystem as it often attracts people who are thinking about getting in to the startup game but aren't quite there yet. Networking is a huge part of being a successful startup. You could treat this as your first foray in to an activity that's absolutely critical for success. Good luck out there, but take your time and be extremely selective. A truly amazing cofounder is 1) hard to find 2) a pre-requisite for success.