stay locked up longer. This is making him see the consequences of his behavior.
I agree with the others, although I acknowledge and feel very sad about how things have turned out. And I can see how hurt and sad you feel, and how guilty.
But the thing is, I agree with Crayola. I know you have younger children at home. Over and over again your son has made poor choices that would put you at risk and put the children at risk should he live with you. I recognize he wanted to come to your home. That was because he needed a place to live.
He is a child still and can't be expected to have the resources and the ability to house and feed himself. However, for a long time he has insisted on making choices that a man makes. Not a good and responsible man. If this were the case, he would still have options. But an incorrigible man/child, a teen on the road to be a man who lives outside of the law. These choice he is making are incompatible with living in a family with young children.
He has chosen to live outside of rules. And he has continued to seek this this every single step of the way. He is the one who has eliminated any good or reasonable option he would have had.
Your work is to accept that your options were constrained by circumstances. Whether it was his behavior. Whether it was the younger children. Whether it is your new marriage. I don't know the whole story. But what I do know is that you have suffered for your child every step of the way. And what I do know is that he has never seemed sincere about trying to reform himself. I am remembering how his grandparents welcomed him with open arms, and he betrayed them, by his acts. And while his Dad may have been ambivalent, he nonetheless brought your son home.
I don't know if those were set ups or not. Maybe it could never have worked out. Maybe these people were either unwilling or unprepared to deal with a troubled adolescent. But the thing is your son has to learn to accept the reality of his circumstances, so that he can learn to make better choices.
And you have to accept the reality of your circumstances. I understand sadness. All of us deal with it. But there's a reality here: You have tried to stand by him, to the extent that his choices and your circumstances allowed. Sometimes life does not offer better options. I am sorry.