Most couples who come to counselling are not deciding whether to separate. They are stuck in a pattern neither of them chose, and they want a room where it can be interrupted.
The argument is rarely about the thing it appears to be about. Money, the washing up, whose family you see at Christmas. Underneath is usually the same question asked a hundred different ways: do you still take me seriously?
A counsellor is not a referee and will not tell you who is right. What they do is slow the exchange down enough that both of you can hear what is actually being said, and name the pattern you have both stopped noticing.
What sessions look like
Usually fifty minutes, usually weekly, usually both of you in the room, though some practitioners will see you individually first, and some couples find that easier to start with. Six to twelve sessions is common. You do not have to commit to a course before you begin.
You don't both have to be sure
One of you being reluctant is normal and is not a reason to wait. So is coming when you are not certain the relationship will continue: counselling is as often about separating well as staying together.
When it isn't the right thing
Where there is abuse in a relationship, joint counselling is not recommended and can increase risk. If that is your situation, please speak to a domestic abuse specialist first. See abusive relationships, or call the National Domestic Abuse Helpline on 0808 2000 247.