Renee, I would not talk to your son about telling you things today. Wait a day or so. If you do it now, he will perceive your talk as being angry, resentful and jealous. He most likely would tell his father what you said if you did.
So, with that in mind....do something totally different... Now, about him sharing what he is doing tomorrow, asking what time he needs to be ready is okay. You may even want to say to him, "son I hope you have a good time w/your dad". Leave it very short and simple. By keeping it short and simple, he has nothing to repeat back to his father.
Yes, it hurts like hell, but you need to look at this another way....he's getting to spend time w/his father. Many children don't have that opportunity. Take the lemons and make lemonade. Be thankful for what time your xh does spend w/his son.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
