No matter what you say, what you tell them, what you want them to feel, your child will learn the most about dealing with separation by WATCHING you. I think it is so important to teach a child that it is OKAY to be sad when their other parent is away (usually deployed in our case) but to also show them how much they are loved and missed as well. The nights when my oldest (then two) had the hardest times when my husband was deployed I handed him his Daddy Doll and talked to him about him. I would ask if he missed him, if he was sad. I let him know that I was sad too but that Daddy loved us both so very much and missed us just as much as we missed him. We would listen to the book that C recorded before he left together. I think it is so important to stay WITH them, to let them know you share that emotion.
When they are so small it is so very hard for them to understand what they are feeling - anger, sadness, confusion. They don't know how to verbalize it. Just asking my little one about certain feelings in the way his two year old mind understood such things calmed him down tremendously - when he could say it and understand it.
Our children watch us - especially when our better half is away. They learn how to cope by watching how we cope. It is okay to let them see us sad - but to ONLY see us sad will teach them that we can't move forward, that we do not live in the every day. We have to teach our children to find JOY while our service member is not with us. Life does not stop - their childhood will not be paused. We must let them share their feelings, must help them to cope with the sadness and we must, we MUST show them how to find the joy as well.