hi, i''m glad you found us again too. i'm sorry about your son and i pray that he continues with his recovery this time. i think you've set a good boundary for yoorself by telling him you will not allow addiction to live in your home.
for me, it took for my family to step away and allow me to suffer the consequences of my own actions for me to see just how out of control my life had become before i got serious about recovery. i'm grateful to them and today i'm clean for a few yrs now. i don't know where i would be if they had not done that.
i believe as long as an addict have all their needs provided for, then like you said, all they have to worry about is how to supply their drug habit. btw, i don't think you were stupid, you were doing what most good parents do to help their kids and usually an addicted won't tell you the extent of their addiction. so try not to beat yourself up. you were just caught off guard like a lot of us has. you and your family are in my prayers.