I think honesty is key for you here. He needs to be aware of your situation - not specifics or any level of detail but if he knows you have been through a lot of hurt he is likely to be more aware of what he asks of you.
You also need to be honest with yourself. Try not to put yourself in one particular category - i.e I have moved on or I have not moved on. It is natural to sway between emotions and feelings and by trying to commit yourself to one way of thinking you will just set yourself up for a fall.
Enjoy what you have with the new guy - if he is giving you any happiness that is a positive in itself. Take each day as it comes and things will develop naturally. By speaking honestly with each other you wont both be sitting around worrying about what you should or shouldn't say.
Hope it works out for you