A co-founder is a long-term relationships that should be built on trust, and passion, and time... time to fight, time to recover, time to build rapport. Ultimately, your co-founder shouldn't be based on *any* specific idea, because the two (or three?) of you could work on anything you are all passionate about, and either experience wild success or learn some great lessons along the way.
An MVP doesn't require a co-founder get built. In fact, the less technical code required the better. You should be able to validate most ideas with some very basic tools: WordPress site, Email list, a set of google forms, and a little love.
I think the most important question to ask yourself is, "Am I willing to have my idea change for the right person? Or am I just trying to find the best person to execute on my idea?"
For what it's worth, I've seen much more success with the former than the latter.