I've discovered in my life and in the life of others that how we embrace our aloneness determines whether it will be toxic or nourishing.
Toxic aloneness is produced by internalized shame. Unprocessed "original pain." Old baggage, unfinished business. So, by it, one fears separation. Or, there is indulgence in addictions, fantasy bond, or unhealthy activities to cover and escape from the pain. Toxic aloneness comes out of being self-ruptured.
Nourishing aloneness, on the other hand, means you've reached a point when your self is strong enough to protect and take care of you. You love and value your self. Instead of continually suffering from old wounds or getting stuck, you've completed your "original pain" work to let you enjoy the joys of solitude.
On the deepest level, aloneness that nourishes is possible when you flow from union with your Creator. As you come to experience growth and bliss in union with God, you come to know your true self. You also arrive at a place where you discover that you are really never alone.