A founder I worked with, let’s call her Sarah, had built a profitable company with her cofounder for six years.

From the outside, the business looked healthy: $10M revenue, a growing team, a product people respected. Inside, they hadn’t spoken live for months. Every interaction was routed through Slack or email, carefully engineered to avoid friction. Sarah had stopped including her cofounder in product decisions. Her cofounder had stopped pushing back.

They both described it as a workflow problem.

It wasn’t.

What looked like a work problem had been building for a long time. And it’s more common than most founders want to admit.

The Pattern Isn’t Laziness

When one cofounder appears to be underperforming, the instinctive read is personal: They’ve lost motivation, they’re not committed, they’re coasting. That read is usually wrong, or at the very least, incomplete.

Research on startup teams suggests that 65 percent of high-potential ventures fail due to cofounder conflict, not market fit or funding (Wasserman, 2012). But the conflicts that sink companies rarely announce themselves. They first tend to show up as performance gaps, role drift, and communication that gets progressively more transactional.

Across dozens of cofounding teams, three patterns show up repeatedly:

Withdrawal cycles. When one founder becomes hypervigilant under pressure—taking on more, moving faster—the other tends to do less. Usually, this is an unconscious stress response. The more one founder compensates, the less room the other founder has to contribute. Unfortunately, the psychologist John Gottman identified stonewalling—emotional withdrawal during conflict—as one of the most reliable predictors of relationship breakdown (Gottman & Silver, 1999). Cofounder partnerships aren’t immune to these dynamics.
Role erosion. This builds on the withdrawal cycle above. As tension builds, boundaries between roles start to blur. The founder who’s “outperforming” begins making decisions in the other’s domain out of necessity, frustration, or both. The displaced founder becomes less engaged, often feeling underappreciated for their contributions, which justifies further exclusion. And it compounds.
Emotional debt. Unresolved tension has a way of collecting interest. Conversations become shorter. Assumptions replace curiosity. Small disappointments get filtered through increasingly negative interpretations of the other person’s behavior. When founders avoid addressing what’s actually wrong between them, accumulated resentment, unspoken hurt, and eroded trust eventually surface as disengagement, criticism, or outright conflict. Over time, each founder becomes more convinced they understand the problem—and less interested in questioning their own perspective.

This unstable foundation doesn’t stay contained. Employees notice. They start reading the room instead of doing their work. Important decisions get delayed because the rules are unclear and decision rights feel murkier than ever.

What Sarah and Her Cofounder Found

The structural business complaints—role boundaries, decision rights, who owned what—were real. But they were sitting on top of something more challenging to address.

Sarah’s cofounder didn’t feel excluded from product decisions as much as she felt cut out of the partnership. Instead of being named directly, the frustration found other exits: critical emails, silence in meetings, and a slow withdrawal that looked, from Sarah’s side, like someone checking out. Sarah absorbed more. The gap widened.

What neither of them had done was name any of it directly.

When they finally did, the dynamic shifted. Sarah’s cofounder shared that beneath the frustration (and even more importantly), she didn’t feel trusted. That landed differently than any performance conversation had. Sarah recognized how her own pattern of suppressing discomfort and carrying everything alone was costing both of them.

The structure was only one part of the problem. The unspoken relational dynamics were the root cause.

3 Things Worth Trying

If you’re in a similar dynamic, a few approaches tend to help.

Start with metacommunication, not the business issue. Most of these conversations start too late and in the wrong register, using performance language to describe what is really a relationship problem. A more useful entry point might be: What’s getting in the way of us working well on this? It’s a small shift, but it shifts the focus back on the relationship dynamics.
Name what’s actually happening emotionally. Conversations about output that ignore what’s underneath them tend to go nowhere. If you’re frustrated, say so. But make sure you don’t use accusatory language. “You’ve been checked out,” is less effective than, “I’ve been feeling isolated in these decisions and I don’t think that’s working for either of us.”
Have the conversation about ownership that you’ve both been avoiding. Performance drift often starts with ambiguity. Unclear ownership, unspoken expectations about time and commitment, and mismatched assumptions about what this phase of the company often contribute. A direct conversation about who owns what, and what each person needs to do their best work, closes a lot of those gaps.

None of these are instant solutions, but the alternative of compounding drift rarely ends well.

Before You Draw Conclusions

Now is an important moment to notice how much of your experience you are currently holding back from your cofounder. If you notice a buildup, pay attention. Get curious about your contribution to the problem. Ask your cofounder for feedback about how your behavior might be making it harder for them to engage with you.

The friction between cofounders is almost always mutual, even when it doesn’t feel that way. The only way to get a more accurate picture of the relationship is to start raising some of these questions and observations.

These dynamics rarely resolve on their own. Left unaddressed, they quietly tax the founders, the team, and eventually the company itself.