It is hard to answer precisely what the chances are that your husband will only get supervised visitation if you file for divorce. Prescription drug addiction and abuse are certainly relevant to visitation, and the evidence you have will be important. In order to limit your husband's parenting time with his daughter to the point of supervised parenting time, you will need to show that the prescription drug addiction and abuse endanger your daughter. If you would be endangered by having to exchange your daughter with him for parenting time, such as if he would use that opportunity to follow you or harm you, then that will also be relevant in pursuing supervised visitation time.
While it seems obvious that a parent with a drug addiction problem who is also abusive is not a fit parent, it is not always so easy to prove in court. You should probably talk to a lawyer to determine the strength of the evidence that you have. For example, the marriage therapists would likely not be able to testify, because their communications with your husband are probably protected. But, there might be other pieces of evidence, such as neighbors who have overheard or witnessed some of the abuse, that a lawyer might be able to help you identify. You might also call some of the domestic violence hotlines to get advice about gathering additional evidence or documents you might need when you file for a divorce.
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