Complex sentence: She eventually left Sandy in the care of relatives in Englewood, New Jersey, for long periods of time, with Sandy enduring many absences from Gellhorn during her travels, and eventually he attended boarding school.
Split into simpler sentences: She eventually left Sandy in the care of relatives in Englewood, New Jersey, for a long period of time. Sandy endured many absences from Gellhorn during her travels, and eventually attended boarding school.