I’m sorry to hear about your situation. It all sounds rotten for you. I think firstly you should ask your 17 year old how them being made to be the message carrier is making them feel. That’s a lot of burden to put on a teenager. Maybe you should look at message only communication, no voices or face to face. Ease into it that way, it’ll give you time to reflect on your reply before sending.

So sorry to hear this! It must be so rough, especially this time of year. I don’t have a lot of advice other than saying that things are still really raw so don’t punish yourself for being emotional, it’s only natural! Conversing via email in a very corporate emotionless manner is fairly common for exes when organising things with their kids. So maybe this would be a good way for you to express yourself clearly without all the emotion of a face to face conversation or a call? It would be better too, than your ex putting your 17 year old in the middle, which isn’t fair on him (your son) at all.