So sorry to hear your story Putto.
People change. I will even go so far as to say people die, and are reborn into their old shell within that same 'lifetime'. The woman I know and loved died some time ago, and reborn was this monster. Likewise with your (ex)lover, you may still be in love with, hoping and praying to find the REAL love you had with that person once before, but he may be long dead inside this person you no longer know.
Of course, I wont say give up, or keep trying. This is something you must find in yourself.
It is devastating, and I am also going through it hot off the press right now. Your mind knows the person you love is wrong for you, but your heart cant let go of the good memories. This community here is lovely. Keep reading, keep posting. It will help some.