Chic, I have been where you are. Even though my son is an addict, the situation was much the same. My husband even gave him a job as a mechanic in his business so that he could have time off for his counseling and meetings during the day as well as working and have the dignity of a pay check to pay his own expenses.
It didn't work, the money went to drugs and the time off went to buying them as he'd say he was going to a meeting...but you know how that works.
My son overdosed 3 times in my home and if I had not been there and called 911 I am certain he would have died. This played on my mind as my home became a war zone and we were all sinking with him into that dark hole of addiction. I kept thinking "if I throw him out, he will die". He too refused rehab, refused help of any kind. The truth is, he might die in my home or he might die outside it, but only God has the power over life and death.
When the day came where I could not live like that anymore, I gave him a list of rehabs and numbers, a list of shelters, a list of meetings and a list of places like the Social Services Office, where he could sign up for some kind of relief. I gave him a bus pass for a month and paid for a month in a reasonable place...no palace but clean and safe...and groceries, and I told him that he had some hard choices to make, just like I had just done and that he could choose to move forward and get help, or he could choose to continue his using and go wherever that led him.
Chic, by the time I reached that place where I could actually do that, I had already buried him a hundred times in my mind because every day he risked his life when he took drugs. By the time I could do that, I was just like you and could see how sick his addiction was making ME and I could not live one more day like that or I knew I would surely die.
So I found meetings and support, I found SR and I found a faith in a God who loves all His children, even his addicted ones, and each morning I say a prayer and give my son's care to God, then I live my day in faith that God can do for my son what I cannot, and I leave the rest between them.
I know your pain, I know how hard it is to be us, I know and my heart hurts for you. If love could save our addicted kids, we wouldn't be here and these boards would be empty. So we do what we can and give the rest to God because in the end He's the only one with any power here, always has been always will be.
I hope you go to your meetings and find peace that will give you the clarity to do what is right for you. That may or may not be what was right for me, but you will know in your heart that you are doing what you must, whether you choose to let him stay or show him his alternatives. We feel better about our decisions when we are balanced and healthy when we make them.
Big hugs from my heart to yours.