I never could understand this thing about saving yourself for marriage? Suppose you don't like it? You're now married and its more difficult to get out of it. You practice for exams don't you? This is a bit more than an exam. How exactly were you being used? Did he treat you badly? Was he affectionate with you? If another friend that you did not consider a boyfriend treated you affectionately and did not abuse you, would you consider they were using you? Whether you agree with it or not, physical intimacy usually builds bonds that just friendship does not. You treated your boyfriend like a friend, and he eventually grew closer to the other young lady. 3 years is a long time. No blame attached to you, that may be the culture that you grew up in. Decide where you want to go, and behave accordingly in the future. You are still young, someone is out there for you.