On a board to which I occasionally post, someone has posed the question of why some curanderos don't allow couples to sit together. Some people say it's hogwash. I don't think so. I think couples tend to interfere with one another during a very private time. I learned that from experience.
So this is what I wrote on that thread:
I'll start by saying that in general--and there are exceptions--ayahuasca is not, in my experience, a group situation. Which doesn't mean you don't drink in a group, but when you are in the medicine, and when you are in your dream, you are very alone. And I think you want to be alone. Scary, yes, but that's what the curandero is there for.
That said, when people come on my trips, I don't force couples to be apart if they want to be together, but I do encourage it. Why? Well, often, one person in the couple thinks the couple is stronger than it actually is. The other person may not feel that way, at least not having come all the way to the Amazon to explore their soul. Sometimes that's confided in me beforehand, sometimes after the first ceremony.
More than that, there is a temptation to watch out for those we love. I remember once when my wife and I were quite close during a ceremony, and at the time we were very much in love, and she was struggling. She was moaning painfully, occasionally cursing under her breath. I tried to leave her alone but eventually leaned over and asked if she was alright.
She simply opened her eyes for a moment and asked what the hell I was doing invading and interfering with her dream.
That was more than 15 years ago and I took it to heart. Even with people who are not lovers, I have a rule that no one, no one will interfere with anyone. I don't care if someone is vomiting on themselves and screaming "help me". No interference. My team and I will see to that person in a way that will not interfere. But if someone nearby, and it happens more often with couples or good friends who are near or next to one another, reaches over and touches that person in an attempt to calm them, or talks to them, or interferes in any way, well, you just have to know that more often than not, that apparent "crisis" came on at EXACTLY the moment when the heavens were about to reveal the secret purpose of that person's life, or the purpose of all life or something else just as startlingly vital. And when you, as a neighbor or lover interfere by asking if you can help or if anything is wrong, well, you took that moment away. That call of "help me" might have been aimed at an angel, but us humans might hear it as a call for help. So when the angel was going to help, us humans interfered and the angel, who has it's own life, simply moved on.
So no interference is the rule. And it's difficult, difficult, for people who love each other, to restrain themselves from trying to help.
That said, I will admit that I have held both of my sons when they were in their early teens and very frightened. And I once asked someone to hold me when I thought I would die from fear. In my son's cases, my holding them didn't interfere. In the case where my fear got the best of me, my cowardice certainly interfered.
So I think the reason that couples are often separated is simply that one will work with the other, trying to help, and even if they don't touch or talk, they will be interfering with the work.
I think it's for the same reason that couples are rarely, in my experience, allowed to diet together. You can't be working on you if you're working on making sure the other person is getting the work done. And you probably can't help the other person do the work. So it's probably better that one diet's in January and the other in March, so to speak.
Just my experience.