One of the biggest underlying reasons that couples come to counselling is because one partner has anxious attachment and the other has avoidant attachment which results in what is called a distancer/pursuer dynamic in the relationship. This is something that they may not be aware of, and they likely won't talk about it in those terms (unless they have already done a lot of counselling in the past, or a lot of reading on attachment theory).
As you can probably guess, the distancer in this dynamic is the avoidant partner, and the pursuer in the anxious partner. It basically means that the anxious partner often fears feeling distant from their partner, and is constantly trying to get closer to the avoidant partner in a variety of different ways, while the avoidant partner feels very uncomfortable with a lot of closeness, and therefore creates distance in the relationship with what they call deactivating strategies.
This episode will focus a lot on attachment theory, so if you're unfamiliar with it, there are a lot of great resources out there. Here are a few to get you started:
Why Anxious and Avoidant Attachment Attract Each Other
Attached: The New Science of Adult Attachment and How it Can Help You Find (And Keep) Love by Amir Levine and Rachel Heller
Listen to the end of the episode to find out more!