If you divorce when your child is a teen, they will have friends with divorced parents and a frame of reference from which to understand their new reality. If you divorce when your child is a baby, they'll never remember a time when their parents lived together. But if you divorce when your child is a toddler or preschooler, you'll need to carefully plan to talk with them about the upcoming changes in their life. It helps to put some thought into how to talk to young children about divorce, depending on their ages.
You've spent a lot of time thinking about divorce in general, and your divorce in particular. Although it represents a huge life change for you, you've had some time to get used to it and you have some control over it. By contrast, the news may seemingly come out of nowhere to your child, and there's nothing they can do about it. The good news is that you have the opportunity to reassure your child by delivering the message in the gentlest way possible. Let's talk about how young children deal with the news of divorce at different ages.
For toddlers, the world revolves around themselves, their wants, and their needs. They have limited ability to understand the concept of the future or what will happen in it. They are also, of course, utterly dependent on you, even if they like to think otherwise.
Keep thing simple, and focus on what's most important to them: their needs. Reassure them that both parents love them. You don't need to use the word "divorce," since that will have no meaning for them, but tell them that you will be living in different homes, and that they will get to have a home with mommy and one with daddy.
Since toddlers thrive on routine and familiarity, you might say as you are going through your bedtime routine, "When you are at home with Mommy, Mommy will give you your bath, help you put on pajamas, sing you a song, and read 'Snuggle Puppy.' When you are at home with Daddy, Daddy will give you your bath, help you put on pajamas, sing you a song, and read 'Snuggle Puppy.'" You may want to keep duplicates of favorite books and toys at both homes to increase the feeling of comfort and familiarity (and avoid meltdowns when a favorite item isn't available).
Don't try to tell your two year old, "You'll see Mommy on Wednesday," because your child doesn't understand when Wednesday is. Be patient as your child asks repeatedly where the other parent is. Offer lots of snuggles and reassurance, and spend extra time with your toddler if you can. It will be good for you both.
What not to do: talk negatively or angrily about the other parent, reasoning that you need to vent and your child won't understand or repeat what you say. The other parent may have left you, and done some terrible things beforehand, but talking about any of that with a young child will only increase their anxiety. They may not understand the specifics of your words, but they will pick up on your anger and stress—and internalize it.
Preschoolers are a little more cognitively advanced than toddlers. They understand a little bit about cause and effect—and as the saying goes, a little knowledge is a dangerous thing. Like toddlers, preschoolers still place themselves at the center of the universe. They may take the little bit of knowledge they have (Daddy moved out) and conclude that it was because of them (because I made too much noise when I was playing). You know that's not so, of course, but to the preschool mind, it makes perfect sense.
Reassurance and routine continue to be important with this age group. Tell them that deciding to live apart is something grownups sometimes do. Reassure them that you both love them all the time. As with toddlers, maintain routines, keep explanations simple, and be prepared to repeat conversations. Your child is trying to make sense of a seismic shift in their world, and you want them to open up to you. If they sense that their questions are annoying you, they may keep their anxieties to themselves, and the worries may manifest in physical symptoms or in acting out.
Ask them if they have any questions. Something that you take for granted, such as that there will always be a parent there to take care of them, may be a source of great anxiety to them. Remind them that if they think of any questions, they can ask you at any time.
What not to say: don't tell your preschooler how much you will miss them when they are at their other parent's home. You want to reassure them of your love, but talking too much about how much you will miss them may make them feel guilty for spending time with the other parent. And as with toddlers, don't badmouth the other parent, no matter how angry you are. It will harm your child for far longer the temporary venting makes you feel better.
To read more about divorce and children's developmental stages, read: