This is going to get very Freudian, but please bear with me.
In psychoanalytic terms, the Self has a narcissistic need to form a relationship with something called the Self-object. That can be anything: a spouse, a pet, a hot dog, a vacation, even a president of the United States.
The Self-object becomes a kind of extension of the Self. The Self desires it, identifies with it, transfers emotional meaning to it, relies on it for ego-strength and even a kind of love.
The Self/Self-object relationship is normal, apparently, despite its creepy name. But it also carries with it certain enormous risks: Spouses …