On the positive side, you are "in love" with your partner. This is at first a deeply satisfying state. You feel intensely alive. Your existence has suddenly become meaningful because someone needs you, wants you, and makes you feel special, and you do the same for him or her. When you are together, you feel whole. The feeling can become so intense that the rest of the world fades into insignificance. However, you may also have noticed that there is a neediness and a clinging quality to that intensity. You become addicted to the other person. He or she acts on you like a drug. You are on a high when the drug is available, but even the possibility or the thought that he or she might no longer be there for you can lead to jealousy, possessiveness, attempts at manipulation through emotional blackmail, blaming and accusing—fear of loss. If the other person does leave you, this can give rise to the most intense hostility or the most profound grief and despair. In an instant, loving tenderness can turn into a savage attack or dreadful grief. Where is the love now? Can love change into its opposite in an instant? Was it love in the first place, or just an addictive grasping and clinging? ...

— Eckhart Tolle

from The Power of Now: A Guide to Spiritual Enlightenment