Kissak, Four days ago you stated that you know he isn't ready. You also said that you believe he is still hung up on the old girlfriend. Those are red flags.
There is nothing wrong with saying "thanks but no thanks." You have outgrown him and his juvenile tendencies. You are the only one who is going to truly be looking out for you. His pattern of walking back out is something you really have to consider. The children seem to be doing so well and will be greatly affected should he do so again.
Is he asking to reconcile or just to move back in for convenience sake? There is a huge difference. Reconciling can be done without him living in the house. Take your time thinking things through. This is not a decision you should rush to make.
*hugs* ~ swl
Look not mournfully into the past. It comes not back again. Wisely improve the present. It is thine. Go forth to meet the shadowy future, without fear. {Henry Wadsworth Longfellow}