My husband also has trust issues and low self-esteem. 6 years into our relationship, and he's still learning how to be open with me. It takes time. Lots of time. Even more time when the cause of those feelings is still involved. In my husband's case, it wasn't until his overbearing mother was cold and buried that he started to let himself relax a bit and be who he wants to be.
One thing I've had to learn is that I can't push him too hard to talk. I tell him that I want to hear what he has to say, and then I have to give him time and space to put his thoughts into words. Half the time, he'll work things out on his own and tell me nothing. It's a work in progress.
“As I am sure any cat owner will be able to tell you,
someone else putting you in a box is entirely different
from getting into a box yourself.” —bisexualbaker