Enjoying alone time is an act of self-love / self-acceptance. Jealousy, and other states of mind that make us doubt the love of others, comes from the fear that "maybe I'm not worthy of love". If you can love yourself, being alone loses its stigma, and for some, is quite restorative.
She is the type of woman who needs alone time. She feels deep, she thinks even deeper. Her alone time allows her to figure out her mood, where her energy is, and how to take each step in life. Sylvester Mcnutt