He is NOT who you love.
That's a confusing statement! If he's not who you love, then who is he?
Manipulators manipulate, charm, and are like chameleons. They become the person YOU want them to be, and they do this so that they can manipulate you into becoming their tool and narcissistic source. They manipulate you so they can use you up, like an emotional vampire. They may use your body, your money, your house, car, expertise, ideas, and more.
How do they do this? They create a False Self - like a character actor - that is based on your vision of a perfect partner. He tells the lies required to get you to believe that he is The One, and to get you into a subordinate position.
He is highly skilled at examining your Authentic Self - the person YOU really are - the core of your personality: your self, your soul, the person your friends and family know, the self with frailties and vulnerabilities. These are what the manipulator looks for: kindness, optimism, believing in the good in all people, someone who thinks everyone deserves a second chance, one who treats people like they want to be treated.
Once he identifies your vulnerabilities, he becomes the answer to your prayers. He becomes what you need, who you want, and creates the man of your dreams. He gives you everything you've been looking for, such as attention, dates, calls, sex, texting, talk of family, babies, and a future. He'll dazzle you with charm and make you feel so special that you are sure he is The One.
Eventually - typically, after marriage or the wearing down over time - the mask drops because maintaining the False Self is impossible for the manipulator. His true colors begin to show, and you'll be left wondering what happened. You're a victim of his narcissistic Bait and Switch.
Don't waste your time mourning the loss of the man or woman you THOUGHT you knew because that person doesn't exist. It is not possible for your lover or friend to return to that person because that mask has been discarded. He will not change. It is NOT because you did "something wrong" or "aren't good enough;" he simply returned to his normal, manipulative, narcissistic self.
Don't fall into the trap of thinking that you can get him back to where he once was. That character is gone forever.