What is the likelihood that courts will grant her joint custody if she voluntarily left our house, had an affair and sold all marital assets?

My soon to be ex-wife is going to be leaving rehab in the next 2 weeks. She is going to a halfway house that allows children to live there. I want primary custody and she wants joint. We have a hearing on Monday for custody. Our child has been living with me the past 6 months. We both claim that we are the primary caregivers. I do not want my son with her at a halfway house (no matter how good it is). I do not feel that it is an environment for him to be in. I want primary custody and I feel that she may have visitation but no overnights.