So unsure of myself

It looks like there is something on his mind.  Something troubling him, weighing on him.  I asked him about it, invited him to talk to me, but he didn't say anything.  Part of me aches that he doesn't open up to me, but for the most part I just accept that that's how it is right now.  I've only been here for a month.  Though we've been talking for over a year, this part of our relationship is still really new.  He's been through a lot, I imagine.  See, I'm not sure on that front, either, because he hasn't shared with me.

It's really hard to be there for him most of the time.  I want to be.  He can trust me, lean on me.  Whatever he needs, I'm here for him.  But can trust me and will trust me are two completely different things.  So far, he's let me in a little bit, but is still hesitant to let me in completely.  Honestly, because of our history, I'm not sure if it's because he's unsure about me, or if it's because of what he's been through.  The result is that I start to doubt myself.

Well, that's not entirely true, is it?  I usually doubt myself.  There are days where I think that I'm perfectly capable of just about anything.  I act with confidence because I am sure that I will do well.  Then there are days when I cannot imagine how I could ever be good at something.  I'm sure that I must be terrible, and I'm afraid to even try my hand at whatever I'm facing.  Really, it's not so much days as it is different tasks.

At work, I'm perfectly sure of myself.  I love my job, and I can see by the looks on the faces of my customers and co-workers that I do well at it.  On the other hand, when it comes to sex, I am completely unsure of myself.  I love making love to him.  Every time with him is so good, it blows my mind.  Afterwards, though, I always wonder if it's good for him.  I've never had the courage to ask, but I wonder.  I don't think I'm any good at it.  It's horribly embarrassing to think that, much less say it out loud.

I'm sure that if he ever told me I was good, my fears would be calmed.  I would gain confidence and maybe even get better.  The problem would be if he told me that I'm right to be unsure.  That I'm not good, or that I don't please him.  If I ever heard that from him...I think I would shut down completely.

Anyway, that's not really the point I was trying to make.

I worry about him.  When I can see something weighing in his eyes, every fiber of my being wants to help lift it from him.  To even have a hope of helping him with anything, though, he has to trust me.  So, then, that's the pivotal question:

How do I earn his trust?