Article continues below advertisementHayden Panettiere has endured numerous hardships in her life, but the day ex-fiancé Wladimir Klitschko asked her to give him custody of their daughter, Kaya, was "one of the worst" she's experienced.Klitschko confronted the actress about the situation when she went to visit him and their child after she finished her second stay in rehab for postpartum depression and substance abuse.