You must understand that a relationship is a partnership, and requires work from both partners in order to succeed. The initial romance stage isn't supposed to last, the relationship is supposed to grow into a real life partnership, and that requires paying attention, learning and growth. It's not a fairy tale—it’s a real life love story, and well worth the work required. If you give nothing, you get nothing. Love is something we create by working together, and one person can’t force it.
Clinging to a lost love can turn toxic: persisting in showing up at your ex's house, calling or showing up at work, threatening physical harm, calling your ex’s family and friends, or otherwise interfere with his or her life, will not only push your ex away, it is illegal in many states, and defined as stalking. Sometimes, clinging is encouraged, wittingly or unwittingly, by an ex who doesn't really want to be with you, but who either doesn't want to 'hurt you' or is still getting benefits (financial help, sex without commitment, you do the laundry, you're willing to take the kids more than your share) that he or she doesn't want to jeopardize. But this one-sided arrangement will not make you happy, and it’s probably time to move on.
Once you're bonded with someone, it's very painful to let go. Since most of us like to avoid our feelings, we don't want to do the grieving that's necessary to let go. But, when you've had a loss, there are a certain number of tears you must cry to let go—getting on with the crying is the fastest way. Also, the dissolution of the relationship might not have been your idea, so you're clinging to a dream—in denial. And letting go is the path to finding the love you want.
I wish you love—whether it is rekindled, or you move on and create something brand new.