My ex husband and I separated when our son was almost 2. He's now 4 and a half.
We co-parent him 50:50, he rarely sees us both together but it's amicable (or at least civil if a bit awkward for us!) when he does.
Both of us have new (childless) partners of almost two years - they each live with us and (at least from what I can tell of my ex's new partner when my son mentions her) invest time in their relationships with our son. I highly doubt he recalls a time when they weren't around, or when my ex and I lived together.
He's just started to ask semi-regularly why Mummy and Daddy don't live together, and I'm anticipating that he'll ask more questions. To date I've said that we didn't want to live together any more but we both love him and want to look after him, which is why he has two houses. And he's lucky because he has four grown-ups that he lives with and love him.
My partner and I would like to find a book or two to help him understand about non-traditional families, step-parents, two houses etc. All the books I can see seem to focus on dealing with the change of separation and/or "new" partners, but he won't really see it as a change, so I don't want to start talking about negative or unsettled feelings which he doesn't even have.
I think he's just more curious about how and why his set-up differs from the traditional families he sees in books / TV / his nursery friends / the rest of his family.
Does anybody have any recommendations, please?