You’re told to find the right person and everything else falls into place. Popular culture sells the same script: meet “the one”, and the hard part is done.

Anyone who has stayed in a long-term relationship knows otherwise.

The appeal is obvious. The compatibility story lets you off the hook. If it works, you chose well. If it fails, you weren’t right for each other. It also saves you from a harder truth: You drifted, took things for granted, let standards slip, and became harder to live with.

Compatibility still matters. It’s easier to build a life with someone who broadly agrees on money, work, family, and how to raise children. But this is a starting condition, not a sustaining force.

In today's episode, Matt and Graham argue that long-term relationship success turns on behaviour, not initial fit. What matters are small ...