Complex sentence: Elsa struggled to adapt to life as a mother and so on Christmas Eve 1991, she left Nick, taking Alice with her but struggling to cope, she gave Alice to Nick, saying that Alice prevented her from having a social life.
Split into simpler sentences: Elsa struggled to adapt to life as a mother and so on Christmas Eve 1991, walked out on Nick, taking Alice with her. However she once again struggled to cope and handed Alice back over to Nick, saying that having Alice prevented her from having a social life.