my ex fiance is claiming I owe him money and is trying to sue me

Gift or loan? These are always difficult issues. If it is truly a loan, is there anything in writing that would evidence the loan? a promissory note? a signed agreement? payment terms? interest charged? have you ever made payments back to him during the relationship? Absent those factors, he will have a difficult time proving that the money he gave you was a loan. If it was a gift, depending on the amount, did he file a gift tax return?  Was anyone present other than you two when there were discussions about his giving you the money and what the intention was? Under Wisconsin law, if an engagement is broken off, the ring has to be returned, regardless of fault or who broke off the engagement. In small claims court, it is possible that the court commissioner treats the money issue much in the same way, weighing the fairness and equity of your keeping the money claiming it was gifted to you, but is argument that it should be returned whether a loan or not, because the relationship is terminated. It is a very difficult case and one in which there is no clear answer on what the outcome might be.