Children are very perceptive and easily pick up on how you are feeling. There is no point disguising how you feel and pretending that life is great post separation, nor do you want your child to think that your life has fallen apart and you can’t cope anymore.
You don’t want them to think that you could not wait to see the back of their awful mum/dad as you don’t want your children to take sides and you don’t want to put all your troubles on them either. Let your peers, adult family members and mental health professionals be your counsellors and sounding board.
Divorce leaves us hurt, angry, sad, rejected and humiliated and what's worse is that the other person will more than likely remain in our lives for the foreseeable future. There is temptation to spend the rest of our lives trying to make them miserable by keeping the conflict strong, but it is very damaging for you, the parent, and your children.
You need to be neutral and non-judgemental when asked about the other parent and need to be strong for your children. If you complain to your child about how lonely you are after the separation it will make your child feel guilty and sad and they will want to "parent" you. It's not healthy for them to be consumed with worry for their parents' ability to carry on.
Remember you are the adult here and are there to comfort them. Your child may want to solve your problems and make you happier. If they want to have a go listen to what they have to say and acknowledge it - don’t knock them for trying to help.
Make sure you notice your child's feelings and try and be present in person and in mind. There can often be a tendency to leave the room when you receive calls from solicitors, estate agents, benefits agencies etc as a result of the separation. If you can, avoid taking these calls when your children are around. Children may hear your conversations about money (the lack of it) and worry. Secret phone calls can also make them feel insecure.
Let your child be a child. It is easy to make your adolescent child or even your adult child a confidant in dealing with your recovery, your dating life or your fears about being alone. Even if your children seem capable of handling these concerns without ill effects, they rarely are.
You may not notice your behaviour changing but your children will especially when it comes to things like rules. For instance you may become more strict about things you did not mind before, or relax the rules. Be careful if you relax the rules as they make children feel safe and if you do become stricter discuss the new rules and boundaries with them so they know what they have to comply to.