[swombat]

I would certainly not take such drastic action based on pattern recognition built out of some HN article.

Would you file for divorce based on an HN article about overrated spouses?

As others have pointed out, it sounds like he does do a fair bit for this company but you're blind to it. The one trick he's clearly missed is getting to this level of distrust with his cofounder. For that, though, it is not clear that you should fire him. Maybe he should fire you...

[gtCameron]

Could not agree more. You are not thinking of firing your co-founder, you are thinking of divorcing him.

No matter what its going to be messy, and you need to be absolutely sure its worth going down that road before you do it.