No longer able to see your child what do you tell them ?

I have now been put in that terrible position where by I am not able to see my son any more. It can happen for many reasons. Court order. Nasty Ex making it hard. Distance between you to name just a few. Well sadly Im now in this position. Distance is my problem. Its simply to far to make the round trip.800 miles if I was to pick him up for a few days round trips. So what do you do ? How do you hope to get through this your self ? More importantly what about your child ? What do you tell them ? Simply to young to understand. I dont want him to think I have simply abandoned him. With his mother poisoning his mind its going to be hard to get him to understand.

I have an brilliant relationship with him. We used to do everything together. After the nasty split with his mother we still managed to see each other a lot. But now arrangements for where I have been staying with him have broken down. So now what. How on earth do I explain to him. Its going to be devastating news for such a young child. I really don't know where to start. He has a bad relationship with his mother. He relies on her just for the basics in life. Food and a bed. Apart from this she struggles to give him the time of day.

Im lost now idea how to go on with this situation.