Watching them with other people and having to pretend everything’s normal when you’re dying inside? That sounds awful. You’re basically torturing yourself. If you’re clinging to whatever scraps of contact you can get, that’s probably a sign you need more distance, not less. The pain you’re feeling is pretty clear about what you actually need right now.
Read this:
Maybe stepping back completely would be better than constantly reopening the wound every time you see them.