Your ex didn't deserve your love, and some would say that what you feel for him isn't love at all because it isn't based on trust or mutual respect. That's not your fault.
Turn your efforts radically inward, investing in what makes you a happier, more fulfilled, better person. Maybe that means beauty pampering (a spa day, a new hair style), reinvesting in time with friends, taking up a new skill or hobby, volunteering, seeing funny movies or doing things that make you laugh, writing in a journal or otherwise creatively expressing yourself, or committing yourself to exercise. Not only will this personal fulfillment campaign help you now but it will also eventually draw healthier relationships your way.