LOL I saw it in the original post and it just went on by.

when my child was three he asked if he had a daddy. his friends daddys lived with them. and he wanted to know where his daddy was.

I was not about to tell him his dad was doing time for rape.

I showed him a picture of his daddy and told him he has a daddy but his daddy lived back in the state we used to live in. which is an air plane ride away. then I diverted his attention from asking for more details by telling him he could keep the picture after we went to the store and made a new picture so we would have one in his special letters and card box and one he can hold on to.

that satified him until he was 4. at which time he came to me and said since Daddy is an airplane ride away can we call him and talk to him on the phone?

I told him sure but I needed some time to find the phone number. For the next two days I followed my ex's moves from prison facility to prison facility by using the prison addresses on his letters to me over the years until I located him. then while my son was in school I called the prison and authorized a collect call from him to me. and talked to him and explained our son wanted to talk to him. And told him as long as he kept the conversations light and not on prison conflicts or our problems from when him and I were together I would accept collect calls from him every saturday for half hour phone calls. (later that got changed to every other weekend because of rate increases in my bills) then my childs father and I decided together how to tell our child the truth without giving him the full reality of danger and so on involved.

Then I sat down with my son and told him where exactly his daddy was by saying - You know how you have rules like wash your hands before eating dinner, and staying on this side of the appartment complex by not going through the fence walk way? He said yes. Then I said well grown ups have ruiles too that they have to follow. What happens to you when you break a rule? he said time out. I said yes and grownups have time outs too only lots longer. I set your time outs because Im your mom. The police set the grown up time outs. you have to do your time outs in a chair. Grown ups have to do their time outs in jail. your daddy is in jail. he looked at me and said oh ok can we call him now? and I told him I talked to his daddy and he will call you on saturday.

From then on son and dad talked on the phone and sent letters. (for the letters I always opened them first and then read them to my son that way I could edit in the telling that information that was not appropiate for his dad to tell him like getting into prison fights and tell mommy Im sorry for bla bla bla crap. after I read the letters my son and I went into my room and put the letters in his letters and cards box so he would always have the letters)

maybe some of this can help you -

Mom and Dad need to sit down and talk about the situation if possible so that they are on the same page. especially if the child is going to have contact with the dad.

give the child a picture of the dad so the child has something tangible to hold on to and talk to if he wants.

Make arrangements for the child to call the dad if possible so they don't have so much homesickness and emotions about the issue. There is going to be some but this might diffuse some of it,

Get dads address so that he can write to his dad.

basically since the dad isn't home make all kinds of opportunities for contact if possible so that the childs feels less abandoned and left out of dads life.