What a difficult spot to be in! The lies are too many and too elaborate to ignore, so I think you’ll want to gather all you have and make an appointment with a couples counselor. (The “find help” tab at the top will guide you to someone in your area.)
I am going to recommend that you NOT discuss this with your boyfriend. I know the standard wisdom would be for the two of you to have an open and honest discussion. But your boyfriend has the capacity to lie and create false identities, all while professing his love. I’d want you be in front of a professional so he or she can be witness to his answers and your responses.
Make the appointment and explain to the counselor that you hope to be bringing your boyfriend, but that in any case you plan on coming in. Set the appointment for a time when he is free. I would not give him much lead time on this — no more than 24 hours. Explain to him you have a concern about the relationship that you wan’t a professional opinion on, and that you prefer he come with you, but you have made the appointment and are going. Tell him only that you do not feel comfortable talking about it alone with him.
Then go to the counselor, either with him or without, and explain your situation. The counselor will guide you from there. DON’T try to talk to him without a third party there. He has hidden much from you and proven to be a good manipulator. Stack the deck in your favor.