And I am so sorry. However, you are the grown up. You can say that if he wonders about anything mommy says he can ask you and you will never ever lie. If he asks you a specific tell him a brief version of the tru th, if he pushes for more then tell him more, only as much as he wants to hear. He needs to feel that mommy is safe and will protect and by acting as above he will know you are safe and will protect. Also, letters, cards, jokes, anything in the mail or even email. Keep speaking with him in some way everyday so he knows you are his dad and are there for him. Find out his school curriculum and his special performance days and go. I didn't say it was easy, it really stinks. I just said what I know about child development. Good luck.