They are euphoric, elated, or manic - but never happy. Happiness is an amalgam of positive emotions.
Narcissists have very few positive emotions.
Stef, she'll never be better off than you. You are MUCH better off. I know how you feel because I worshipped the ground that my ex-N walked on. Time to go night-night. Most of us have just come out or are trying to come out of relationships with people who have been absolutely toxic to our lives.