I told him not to worry, to just write one list and we'll sort it out.
'OK', he said, 'And then after Christmas I'll choose which toys I will keep here, and what I'll leave in my other bedroom.'
His other bedroom. For some reason his words cut through me like ice. My son has another bedroom. I have never seen it but I know it has a Star Wars theme. I know it is bigger than his bedroom at 'home'. That he has Lego models arranged on the floor. That he has pyjamas just for there. That his bed has a duvet that is 'thick and wobbly and feels like jelly'.
He tells me these things randomly and with excitement. And every time my emotional reaction to it catches me unawares.
We were visiting my parents when he said about the duvet that was like jelly. I excused myself to the bathroom. There is something very disconcerting about listening to your child talk about a bedroom - their bedroom - that you have never seen or have anything to do with. That has been arranged and decorated without your input. And to have to listen as other people ask questions about it.
When I first held my child in my arms eight years ago I had big plans for him. For our family. I never, ever thought, as I decorated his first nursery, bought him his first bed, arranged books on his bookshelf, that whilst he was still of primary school age he would suddenly have a second home and another room. It never crossed my mind that he would ever be put to bed and tucked in at night without me. Or that he could ever wake in the night with a nightmare or a fever and I would not be there to soothe him.
A colleague asked me about access arrangements this week and how one coped as a parent when a relationship breaks down; how as a mum or dad you can bear to be apart from your children, to have to share the with a non-resident parent.
'I don't think I would be able to,' he told me, 'I couldn't bear the thought of not living with my children even for a weekend.'
'You just have to get on with it,' I said nonchalantly.
It was either that or cry.