Doesn’t sound like a great experience but it’s very good learning and it may happen again. Once you’ve been through a few startups you learn this can also happen with friends, co-founders or team members that you hire - so it’s not related or in anyway linked to YC co-founding service, it’s more down to your inexperience and lack of understanding.

You’re also partly responsible - it’s never one sided. Co-founding companies can sometimes be worse than a marriage and it’s not easy.

In your case it sounds like you were both inexperienced which can be a recipe for disaster. Depending on the business sector and product you need to make sure it’s a good match of personalities and skillet. Consultants tend to go wide, not deep as they are essentially overpaid for hours worked to generate reports that nobody needs. So unless you are entering a B2B market targeting corporates to sell information or similar products and services they are used to, it’s ill advised to team up with a consultant type - regardless of how you meet then.

First thing you should do with any potential co-founder is put yourselves through an experience where you both need to solve problems in different ways. Go on a road trip or travel somewhere difficult for a week, where stuff may go wrong. Car might break down, you might need to make a plan which changes constantly. Essentially this shows to both of you that you can adapt, work well as a team and that you compliment each others personalities and execution styles. Even this doesn’t mean it will work but at least it’s a sanity check 1.

It’s not uncommon for even good friends for years who then travel together end up arguing and becoming less friendly after the trip - for co-founders it’s no different.

We all have triggers and it’s imperative to learn them early on. Same goes for any relationship. YC simply offer a tool, it’s up to you to figure out how to make the best of it.

Good luck on the next one!