Hugs to you, SBD, because I know how hard this is to do.
I let my son live at home many times, always with rules and boundaries in place and always with promises from him to respect each one of them. Sadly, every single time it ended badly. If I let him stay my home became a war zone, and a crime scene because both drugs and stolen goods were stashed on the premises, and my own goods went missing, and not a safe place for me to be.
I learned that whether I let him stay or kicked him out had no effect on his decision to use or to get clean. Many times, he checked into detox and at least gave it a try.
I learned that it wasn't about me kicking him out, it was about his having a choice to abide by my rules including no drug use in my home or to live somewhere else. My son made choices that eliminated the possibility of living at home. I only enforced a consequence that he knew existed if he made a bad choice.
What helped me sometimes was to give him a list of detox's, rehabs and meetings, and also the phone number of a men's shelter that also offered help to those who asked. That gave him another choice...he could choose any of them and be safe and get clean...or he could choose to live on the street. Either way, I knew I was powerless over his choices so I would say a prayer and give his care to God.
Finding meetings helped me regain my balance and find my sanity again, maybe try a few and see if they don't help you too. I couldn't control his addiction or recovery but I sure as heck could do something about my own recovery and for me, sooner was better than later.
Please know that you are a good mother no matter how this unfolds. We do the best we can, and that's all anyone can do.
I will keep you and your boy in my prayers.
Hugs from this mama's heart to yours.