Advice from you with AD(H)D on how to break it...

So, I've been dating a guy and am totallty convinced he's got ADHD. Problem is he comes from a country that I know doesn't have a wide awareness of the diagnosis. We've reached the state where problems are kicking in (his focus changed from me to his new job and I feel rejected) and I've had to withdraw to protect myself, and he's acting defensive, and so on. I've tried to communicate without making him feel like he's a problem, that our brains just function differently and so on... But I see how defensive he gets, and I know this goes far back, as for all of you, with feeling insufficient in relationships before. So I figure it might be a help for him to understand this disorder and that he probably suffers from it.

But - how do I go about? How would you have liked to hear it? How did you hear it, and how did it make you feel? Which way is the best way to break through the defensiveness? Or is it best to take it slow?

Do you have any good links that I could send him? I'm thinking sites that don't paint it as a horrible stigma or so...

I would be really grateful for your help and thoughts on this. Don't know yet if I'm strong enough to continue (or if he wants to, now that his focus has shifted), but I'm really concerned about him as a friend anyway.