Trust is one of the most talked-about words in co-founder partnerships - and one of the least defined.

We use it constantly. “I trust you.” “I don’t trust their judgement.” “Trust needs to be rebuilt.” But very few teams ever stop to ask: what does trust actually mean to each of us? The truth is, trust is deeply personal. And highly subjective.

For some people, their trust might be more evidence-based. I trust you when you do what you say you’ll do. When you deliver consistently. When your output matches your promises. For others, trust can be more relational. I trust you when I feel safe with you. When you show care. When I feel emotionally supported or understood.

No model is right or wrong - and most of us hold a blend of several trust definitions, which also change depending on context, and evolve over time… it’s complex hey, people are complex! That’s what makes them magical. But the tension often comes from the fact that we assume our trust model is shared.

What I’m hearing is that you trust your co-founder as a person. But when it comes to trusting their business decisions - something feels shaky. And that’s important. Because trust in character and trust in competence are different layers. And both matter in a founding team.

So there are two strands to explore here…

The first is internal. When you feel the urge to double-check or step in, ask yourself, what’s happening within you at that moment? Is that urge about risk tolerance? Control? Standards? Fear of consequences? Fear of how it reflects on you? A previous decision made by your co-founder that didn’t land well and it’s stuck with you?

Has this dynamic shown up before in other relationships or roles? Are you someone who feels safest when you’re closely involved? Does contribution equal worth for you - and stepping back feels like minimising your contribution? None of these questions are accusations, or judgements. They’re ideas of how to understand yourself more deeply.

The second strand is structural. Have you clearly defined how decisions are made? Who owns which decisions? Which ones are made independently, and which ones are joint? What metrics you’re using as a marker of a “good” decision?

Sometimes what feels like mistrust is actually ambiguity. If roles and decision rights aren’t clear, it’s easy to slip into the the energy-draining habit of second-guessing each other (and yourself). Ambiguity can breed anxiety. And anxiety can look a lot like mistrust.

You asked if this is a red flag. Instead I’d see it as a signal that something needs designing more intentionally, not necessarily a warning that something is broken. The difference is whether you continue to let this build up inside of you - potentially leading to a bigger crack in the partnership - or whether you do something it about it now. Using it as an opportunity to strengthen the partnership.

Trust isn’t static. It’s built, eroded, rebuilt, and clarified over time. And in a growing business, what’s required at one stage may not be the same as the next. So address those two areas - the internal and the structural - and intentionally design the next version of this partnership.

A simple starting point? Look at both strands together.
First: how are we feeling about our structure? Are ownership and decision rights clear? Where is there ambiguity? How could structure be strengthened?
Then, trust: what does trust actually mean to each of us, and how do we build it in practice? What strengthens it? What erodes it? How can we best design our partnership with these insights in mind?