No. Sure, being a single founder challenges everything about you. Likewise, being a cofounder challenges everything about that relationship. I think it's better to 'settle' for finding success outside of YC, etc. than to settle on a cofounder, especially without history. I think being a cofounder tests a relationship and your compatibility even more than marriage at times. Don't do it just to check a box on someone else's list.

Plus, confounding a company together is hard, being a single founder is harder, but I think bringing a second founder in later is the hardest maneuver of them all.

You will resent the decisions he makes concerning your baby without your history in the project. He will resent the lack of immediate trust and freedom.

I don't say this to discourage having a cofounder that you think is a perfect fit. That would be my #1 choice of course. But being a single founder is worlds preferable to having a cofounder setup that goes sour.