Children should be told that some things will stay the same while other things will change. It's best to have some things that will stay stable in their lives to talk to them about. This will help them hold onto some sense of normalcy, and should reduce the anxiety they feel. Even giving basic things such as “you'll still have a snug bed, and your favorite blankie to snuggle up with. You'll always have one of us right there by your side. You'll still have one of us to tuck you into bed at night.” These basic stabilities offer a small degree of comfort. If you can further explain that they’ll still take dance lessons, go to the same school or be able to have certain friends over, that's even better.
Next, follow this basic explanation with some of the following discussion points:
1. Divorce ends a marriage, but it does not dissolve family
Reassure children that even though you are ending your marriage, that doesn't mean you are ending your relationship. It's just going to be a different type of relationship. The two of you are connected together via the kids, and will always have some type of relationship. You're still family, even if not living under the same roof. Assuming the two of you plan to be civil with one another during and after the divorce, you should explain that the two of you will become more like friends, talking and seeing each other periodically while partnering to raise them. If things aren't going well, it's best to cool it on the "friend" talk (rather than lie to them) but you can still explain that you'll have an ongoing relationship of some kind. Your relationship to each other shifts from being husband and wife to being part of a family that is more like Uncles and Aunts or brothers and sisters.
2. Explain the difference between adult relationships and parent-child relationships
Why can parents divorce each other but not their kids? It can be difficult for kids to discern the difference between your relationship failure with each other and how it relates to your bond with them. To help address this issue, you should explain that adult relationships are different than that between a parent and child in a couple of key ways:
A) First, it's different because adult relationships are chosen, whereas children are people given to their parents to love and take care of. Therefore parents love their children unconditionally.
B) Children are, quite literally, a part of their parents. So whereas kids are shaped and molded by each parent, adults are more stubborn and set in their ways. Their personality has been forged over a much longer life, and it's harder for them to change. Children are like soft clay, and each parent plays a role in shaping that clay into a very special little person that is a kid after their own heart. Adults are more like a clay pot that has already been hardened in the furnace, and can't be molded as easily. When adults get together and marry, they are like clay statutes that have already been somewhat hardened. Sometimes they turn out to be a perfect fit for each other. Other times, though, after a while, some people may start to realize they're not such a great fir for each other. They begin to chip at each other and rub each other in too many of the wrong ways. When this happens, it's harder for them to adapt, since their personalities aren't as a malleable and can't be changed very easily.
C) Even among parents in happy marriages, most would tell you that for as much as they love each other, their spousal love cannot compare to the love they feel for their children. That if their love were put on a scale, it couldn't compare to the devotion they feel towards their kids. Tell them this! Have a heartfelt conversation about the feelings you had when they were born, and how it's a love unlike any other love you've ever experienced before. It's entirely truthful for most parents, and will be a satisfying explanation that kids can accept.