Leave the cheating dog!! You will be surprised that you can actually quite easily manage without him. Initially its difficult but after a while you get used to it. With regards to the children....NEVER stay in an unhealthy relationship for the sake of the children...it will one day come to haunt you. my motto...cheat once i forgive you, cheat again and that is the END, because he will always be cheating and hurting you. All the best and you are in my prayers.