Im going through a divorce and so is my boyfriend, they are both filed but not final. Can we cosign a loan for eachother?

The general rule in Wisconsin is that any new debt that is incurred after the date of filing for divorce, is the obligation of the person who incurred the debt; if you incur new debt, your respective spouses will not have any obligation to pay the debt; instead, you are creating new debt that you will be responsible for and if your relationship goes bad with this new person, you could be left holding the bag on the entire obligation.