Hi Lost4words,
I would probably hazard a guess that the ‘not high’ partner you know and care for still loves you, but the ‘high’ partner loves someone else. There isnt a lot you can do about it though, and nothing, not even your son, is enough to keep him.
He might wake up one day and realise that he’s lost the best thing thats ever happened to him, but you shouldn’t put your own life on hold waiting for that time to come, if it ever does. Probably while he’s still using it won’t, and at a guess his new woman probably uses too.
Its painful to see, its gut wrenching, I get that. But honestly, keep doing what you are doing, find happiness, let him see his son when he wants to and as long as you know he’s not high when doing so.
It’s not your problem to solve, and you wont solve it, it will tear your heart out over and over again.
Sending love