I'm so sad for you that's he has ground you down so much that you just can't see what your own life and happiness is worth. And it is not equal to him.
Have you always been so passive in your life?
I think personally you're still in shock. A person will only tolerate this kind of treatment for so long until they snap. Something will happen one day to trigger that anger but why wait until then? He will do or say something that will kick something off but it isn't healthy to be so codependent here.
You're still running around after him like you're his skivvy and he's letting you. He has absolutely no respect for you but then I don't think you respect yourself either. Do you think you're generally a people pleaser? I think you're in safety mode. You're still acting the role you thought you'd had for life and your best friend has ripped it away from you and now I suspect you don't know what to do or who you are under neath that role.
I have experienced suicide too in my close family and I know it made us go into safety mode as a family unit. I did for about 10 years wasting my 20s. I needed therapy to undo some of it.
I think one day you'll wake up and realise this is just one man and he was never worth it. He might have been your best friend but he isn't yours. Would you treat your best friends like this? I suspect you would not do.
I'd like to know, if you'd come back with food poisoning, would he have come straight around to look after you and be honest with yourself. Would he have ironed your clothes before you went off on a dirty weekend with another man? I mean would he really?
I get it, you've always had his back and a habit of 30 years is hard to break. It will take time and if you find it too hard to wrench yourself away immediately, do it a bit at a time and be less available.
He has an emergency? Let his fancy woman deal with it. Let him have the reality of not having you there, the rescuer, to pick up all the pieces of his life while he gets to go have his fun with his side pieces.
There is 2 methods you could apply to help you in this. Grey rock method and let them mode. If you google these, it will help you put a bit of distance between you both while you heal. You cannot heal from the same person who dealt you the pain.
He has shown you who he really is. A truly selfish individual. If you were my mother, I'd be doing everything I could to help you not be so wrapped up in him anymore. But if you allow yourself, you can unmesh yourself and find a life for you. You've done the hard part. You've left physically but the emotional part takes longer.
I suspect he wasn't that worried when you left as he knew you'd still run and help him when he needed it. You are no one's slave remember that but he's trained you well.
I really wish you'd find that anger soon. How dare he treat you like this. But some people are only this way. He's probably been like this for years but you've not noticed due to the family mode and you putting him on a pedestal.
I'm sure there were lots of good times together. I aren't taking that from you. Your whole life wasn't a lie and you got your beautiful babies out of it.
But this next chapter is a learning curve for you. Don't cling to whatever dregs he offers you anymore. You deserve so much more. You sound so ground down with everything life has thrown at you and I'm sorry you got the shit stick I truly am.
I can't wait for that moment when you realise who you really are, it will be very different to what the world told you were.