It sound to me like he's trying to play me.
Most Helpful Guy
He can work on his trust issues give him the space he wants , u guys can still talk and u can be there for him seems like u really love him so u can surely keep contact with him trust issues is something really hard to fix you can, but i am sure if he see your there for him you both can overcome it
Most Helpful Girl
My bf has the same issue, all of his past gf have cheated on him witch has left him with trust issues, not only that he was bullied for a long time.
Sadly those trust issues will not go away in a flash, it does take time. But the biggest thing you can do is support him and tell him how you feel. It will all work out in the end c: