I know I am sometimes scared by how deeply I am willing to submit to my lover/Master--and we were friends for so long before our relationship became sexual that I already had a huge level of trust with him. Maybe you could talk with your master, and see if you could start small with the trust issue? Trust him with a minor thing, with a safe word in place so you can escape if you panic, until you are comfortable with that? Then you could build on that. Or you might learn that he just isn't the one you can let go with. I'm not trying to break you up--I know way too little to even suggest that--but there is always the possibility that you two of you are not the right match.
I am married, but I could not really submit to my husband. Why? I dunno. But I can completely surrender to my lover, and I can't tell you why there, either. I hope you find an answer that makes you happy-good luck.