How should I tell my children?
You can talk to your children as a group, or individually (if they need to know different things because of differences in their ages or how grown up they are).
You may want to practise what you will say and anticipate the questions that the children will ask. It is important to talk in a language and at a level that each child understands.
It is helpful to create an environment in which your children feel safe and in which they feel able to ask questions, even if they feel sad and upset. Set aside plenty of time, when you know that you will not be interrupted, and let the children know that you have plenty of time to discuss the situation with them.