I feel like my cofounder argues with me and is undermining during board meetings. What should I do?

First, that sucks. It sucks to be in business with someone who’s not behaving well, and who may not appreciate the harm this particular situation can cause. 

Next, get over yourself. You chose to work with this human and there’s no way to unwind it now. You made a company together! Your only choice now is to figure it out.

A cofounder damaging you in the boardroom is a symptom of a bigger problem. Something has happened, something’s dramatically changed, or something is in the process of going really wrong. Off the top of my head, your cofounder could:

• Have a bigger ego than when you started
• Have lost faith in your abilities
• Have turned against you
• Have been turned against you by an investor
• Have been turned against you by another cofounder
• Think you’re doing a bad job
• Think you’re not listening to them
• Think you’re not smart enough
• Think the company is going down a bad path
• Not like the fact that you’re the CEO and they’re not
• Be in a bad head space
• Be tired
• Want out

Some of these are you, some of these are them, and some are the intersection of the two (or three) of you. It’s now your full-time job to find out because every single one of the things listed above is a fundamental risk to your company and/or your position. 

It may or may not be easy to find out what’s going on in their brain. You can try to ask directly and maybe they’ll tell it to you straight. (And you better damn well sit there, listen, and not say a word back!) Maybe they’ll tell you some of the story but not all of it. In that case, you have to probe: “What do you mean by x?” And if they’re not telling you anything, you may need to consider a mediator. At my last company, there were times when cofounder communication had broken down and we turned to a founder therapist. It’s couples counseling, not executive coaching, and dives into the basics. It’s here that you may find out your cofounder experiences feelings so rarely that they truly are a sociopath—or that they look up to powerful white men like they are the sun that shines in the sky.

So what do you do when you find out what’s actually going on?

• If it’s them: The scenarios in which they’re tired or want to leave the company or need to make more money or are not being fulfilled in their current role (whatever it is) should be fairly straightforward. Want out? Put together an exit plan and package. Need a different set of responsibilities? Find them a new job in the company. 
• If it’s you: Let’s say you’re not listening or there are repeated scenarios in which you aren’t doing a good job or you’ve made some decisions for the company that have backfired. Then you need to take a long, hard look at your own behavior and performance. What’s going on in your brain? Are you tired? Why are you making repeated decisions that are going against the grain? Why can’t you hear other people? Get your ass into gear, get your ego in check, and adjust. The more openly you admit that it’s you—and the faster you implement change—the better. 
• If it’s the two of you: Usually it’s some combination of not listening and arguing. The key here is for both of you to admit it’s broken in order to take the first step to fixing it. It’s possible a therapist is your only hope.
• If they’ve already turned against you (by a cofounder or investor): This is a hard one to be repaired. In most cases, either you’re going to stay or they’re going to stay. There is a long-shot situation in which you can repair things but, even if you do, the instigator has already succeeded in causing a cofounder schism and knows they can do it again. That’s a company death knell.

In all of these cases, you still have to reset the relationship with the board. How? “I’m sure you’ve noticed that XYZ hasn’t been working and we’ve noticed that as well. We’ve put together a plan for addressing XYZ concern and I appreciate your support in helping us implement it.” Cofounders should ALWAYS present a unified front to investors. 

Keep pressing to neutralize the threat and don’t give up until that’s done. Good luck.