What do I tell the children?

The truth, at their size. Children need three things from this conversation: that this is a grown-up problem and not their fault, that both parents still love them, and a clear picture of what is going to happen to them in the next days and weeks. Everything else (why, whose fault, what the other parent did) can wait, and some of it should wait for years.

What children actually need to know

Children think about separation in concrete terms. Where will I sleep? Will I still go to my school? Who will pick me up? Can I keep my room? Will I see Dad on my birthday? Those questions matter more to them than the adult story, and answering them clearly does more to steady a child than any explanation of the relationship.

So before you talk to them, know the answers to the practical questions, or at least know which ones you cannot answer yet and say so. "I don't know that yet, but I'll tell you as soon as I do" is a complete answer. A made-up one that turns out wrong costs you their trust.

By age

Under five. A few sentences. "Mummy and Daddy are going to live in different houses. You'll live here with me and see Daddy at the weekend. We both love you very much." Expect to repeat it many times. Expect regression: sleep, toileting, clinginess. That is them taking it in, not a sign you said it wrong.

Five to eleven. More detail about logistics, and room for questions. They will often ask if it is their fault, directly or sideways ("if I'd been better…"). Answer plainly: no, this is between grown-ups, and nothing you did or could do would change it. They may also ask you to fix it. Be kind and be clear that you cannot.

Teenagers. They know more than you think and have probably been waiting for this conversation. They deserve honesty about the fact of it and still need protecting from the detail. They may want to know more about why. You can say it is private between the two of you, and that they can ask again when they are older. Watch for them taking on an adult role, looking after you or a younger sibling. Thank them and gently decline it.

What to leave out

Blame, even deserved blame. Money. Anything about the other parent's behaviour towards you, unless the children witnessed it, in which case name what they saw without characterising the parent: "You heard Dad shouting at me a lot. That wasn't okay, and it's one of the reasons we are living apart. It's not your job to sort it out."

That last line is for children who have lived with one parent controlling the other. They have usually seen more than you know, and the worst thing is to pretend they saw nothing. The second worst is to make them the judge. They need to be allowed to love a parent whose behaviour was wrong, and that is a hard thing for the other parent to hold.

What this might mean for you

The free module Children: what they see goes through what children take in from a home with conflict or control, what it tends to do to them, and what helps afterwards. It is written for a parent who is worried they have already done damage, and the short answer is that a steady parent who talks to them now does more good than the last few years did harm. If you are separating from someone who controlled you, Co-parenting when control was the problem looks at how the children's contact can be kept safe and how to stop them being the channel for it.

If a child is distressed and you want someone trained to talk to, Childline (0800 1111) is for them. Family Lives (0808 800 2222) and Young Minds' parents' line (0808 802 5544) are for you. If you are not safe at home, the National Domestic Abuse Helpline is on 0808 2000 247, 24 hours.