My man is also thousands of miles away. The only person that I had told all of my baggage to before him was a police officer.
Saying it out loud to my bf was.. was as if my soul had been purified. A ton literally lifted itself from my shoulders; cos I had been keeping all of that stuff inside me forever and simply just saying it out loud helped me so much.
Since we're so many miles apart, I had to do it by e-mail so "Out loud" isn't exactly correct, but you get the idea. It took me 10 hours to write that e-mail and as I was writing about the traumas, in detail, it was like I was forcing myself to confront what I had been trying to ignore for years.
I had never spoke to a therapist about it, I just wanted to lock it in a dark corner of my mind and pray that it would eventually go away by itself. That tactic never works though, you've gotta confront your traumas and release them.

I honestly suggest that you either write him a letter or an e-mail; don't worry about it not being personal and all that - as long as you're telling him about your traumas it WILL be personal and he will appreciate it. You could call him and say "I have something that I've needed to tell you for a long time, I just haven't had the guts, and it's so long and complicated that I figured it would be best to write it in an e-mail".
The reason why I want you to do it in writing is because it's uh... quite painful. I cried the whole time while I was writing it - 10 hours! And I had to force myself to keep going, and that in itself was therapeutic. My finger would be on the backspace key and my mind would tell me "delete this e-mail and forget all about it, this is a terrible idea" and I had to slap myself out of it and keep writing.

It's incredibly therapeutic to tell someone about it. I told my bf more than he needed to know, but I needed to get it out. I still go "why did I tell him that?!", but when it's allowed me to be honest and have more confidence in myself; it's totally worth it. And he trusts me so much more now - he had trust issues because I had mine, and he hates secrets and dishonesty so he really appreciated that I let everything out.
And letting everything out like that is in itself proof that you do trust the person.
Going through the traumas again made me understand it all, and I stopped blaming myself, and I discovered SO MUCH MORE about myself, my lack of sanity and the incidents, and I had to admit to myself that it wasn't my fault.. and that's a hard thing to do.

I know this is a long post, but I really cannot stress enough how AMAZING it felt to get it out. It was like I didn't even care about the consequences, I just wanted to laugh and run down the street shouting "I'M FREE!!!!!"; that's what it felt like! Freedom!

My advice:
Sit down, get comfortable, open Word and start typing; and write as if you're intending to send it to him. You don't have to send it to anyone though - not yet, you can stop writing whenever you feel like it and continue writing when you're ready again. Just do it as an experiment, and push yourself as far as your sanity will let you.
Once you're finished writing it, read it again, then delete it.
Writing it without sending it to anyone is therapeutic for you, because when you let things out like that it forces you to stop ignoring it; and nothing can heal if you pretend that it isn't there.
In my opinion, you should write the whole thing in one day - because if you do it over several days there's a big chance that you'll cave in to the urge to stop writing, and the effect you get from it won't be the same. It's an intensive self-help thing.

I wrote my first draft on my blog, and I published it and it was public for 1-2 days before I took it down. Then I spent two weeks thinking about everything, clearing up my head, putting the pieces together - and then I wrote the e-mail to him.. another 10 hours of crying. But like I said; I'm free now.

I know it's very Freudian, and it's not easy, but the prize is oh-so-worth-it!!