It is the most common sentence on a first call: I would come, but my partner will not. It is usually said apologetically, as though it disqualifies the person from getting help. It does not.
Start by noticing that the refusal is rarely indifference. Somebody who did not care would shrug and go along with it. Refusal takes energy, and that energy is nearly always protecting something specific.
In my experience it is one of four things. The fear of walking into a room where two people gang up on one. The belief that private matters stay private, and that a stranger has no business in a marriage. Straightforward stigma — the idea that needing help means the marriage has already failed. Or a previous attempt that went badly, in which they left feeling blamed and have quietly decided never again.
Which one it is changes what you should do. If it is fear of being outnumbered, saying the coach speaks to each of you separately first removes most of it. If it is stigma, the word coaching often lands very differently from counselling. If they were burned before, the honest acknowledgement that the last one did not work either is worth more than any reassurance.
Two things reliably backfire. The ultimatum — come or I am leaving — which gets you attendance and nothing else, because a person who is complying is not participating. And the ambush, where they discover the appointment on the day. Both confirm exactly what they were afraid of.
What works better is smaller. Say what you want for yourself rather than what is wrong with them: I want us to stop having this same fight, and I want help doing it. Invite them to one conversation, not a programme. Offer that they can ask the coach anything before agreeing to anything. And then let it sit. Pressure applied to a person who is already braced only deepens the brace.
In the meantime, come on your own. This is not a consolation prize. A relationship is a system, and systems respond when one part of them changes. When one person stops running their half of the loop, the other has nothing to push against and the whole exchange changes shape.
That is also, in practice, the most common route to a reluctant partner joining. Not persuasion — evidence. Something in the house is different, they can feel it, and at some point they get curious about where it came from.