A Bergen County man was charged with child endangerment and sexual assault Friday after prosecutors say he physically and sexually assaulted two children, the Bergen County Prosecutor’s Office said. Milton Guallpa-Guaman, 45, of Rochelle Park was charged with two counts of second degree sexual assault and two counts of endangering the welfare of a child, the office said. An investigation was launched Wednesday by the county prosecutor’s office and Rochelle Park police after the Division of Child Protection & Permanency referred an alleged case of abuse of a child, authorities said. After the i…