my wife is an alcoholic

Proving that the other parent is an alcoholic in court can be difficult. You will need objective evidence; drunken driving convictions; disciplinary issues at work; prior alcohol or drug treatment. Absent that, when you allege they drink too much, they will deny it or claim you are blowing things out of proportion. Your children cannot typically be called as witnesses (that is rarely allowed in Wisconsin). If there are family or friends who would come to court to testify, that could also help your cause. Certainly, if in fact they have a serious alcohol dependency issue, it can affect the placement of your children and court orders can be entered to prohibit the consumption of alcohol while the children are in their care.