From experience with this exact thing; he is torn. Torn between his feelings for you and everything he was ever taught by his family. He fears disappointing them, as well as being disciplined and shunned. Right now he is in self preservation mode. Reality has struck and he is trying to save himself. He more than likely, believes that if he is disfellowshipped, his actual life is on the line, if armageddon were to come, before he is reinstated. He is in fear for the only life he has known. Yet, if he does truly love you, he's going to start missing you, and try to reinstate contact with you, probably sooner than later (if he hasn't already) This is a rollercoaster that can last for years. Are you willing to go through that for him, even if you might not end up together, in the end? My best advice to you is, be strong. Let him know you love him no matter what, but if he won't choose you, over his family, you're gone, for good. Period! And mean it.
Truth is, He can still choose you, marry you, and remain a witness (as long as you're ok with that. I recommend you do extensive research into what that would mean for you and any children you two may have) He will just have to make sacrifices, which he will do, if he truly loves you. You need to be willing to live your life, with or without him.