The indifference when you finally just let go of that person -- no more affection nor anger nor hurt. They are gone, and you are done with him or her. this is not, alas, a common word, and it would be hard to create drama out of the feeling, but it's still an important stage. And, also, it's potentially useful as a way of telling someone "I love you, I'm just not in love with you." From Greek, from an-, not/without + agapésis, affection.
I'm sorry, Helen, but I have to leave you -- I've been struck with anapapesis.