My Ex and I share custody of my 7YO DS.
We have him pretty much 50/50.
I have remarried 2 years ago and we have a lovely stable happy house, Ex and his gf live in a house she owns 2 roads away and all in all it's been the sort of co-parenting relationship that you would aim for.
I left Ex because of his drinking (mostly) and all the things that came with that. (There's some posts on here that I did over the years explaining that although I think I have changed username) He cleaned up his act, or so I thought, held down a job and met a nice GF. They dated for over a year before she met DS, and I met her first and we got on, my son loves her (and her dog) and is really happy in both homes.
Anyway it turns out his drinking has taken a turn again (as it always did) not whilst my son is there, but she messaged me a couple of times saying she was thinking of breaking up with him and wanted to talk to me about it as obviously it would affect DS. Talking to her (and I've been so careful to not lead the conversation) is like looking back at myself 6 years ago and I know she is doing the right thing to end it.
She has told him this past weekend, and text me this morning to tell me so that I could prepare to support my son.
He's already got so much going on right now, just about to move from Year 2 into 3, I'm 36 weeks pregnant so he's expecting a sister any day now (but also he's going to be giving up all the only child perks) and now he's going to lose his dad's GF and dog and the home that he thought was safe.
My Ex hasn't told him yet, and I want to prepare for how I can maybe support him through this. I don't know anyone who has been through similar. Does anyone have any experience of how to do this. He is a resilient and astute child who appreciates a straightforward approach, he's lost a grandad and dealt with that well, but I just feel like this comes at such a vulnerable time for him.
Any ideas or suggestions/or books I can read greatly appreciated.