Question about anger management in relationships!?

My boyfriend and I have been together for a while now. He's my best friend, my lover, my everything, and we love & care about each other very much. The problem is that my boyfriend has severe anger issues that he is desperately trying to handle himself, which isn't working out too well. These anger issues are NOT directed toward me whatsoever. They are directed normally towards things that are to most people considered extremely insignificant, like someone taking too much time to accelerate at a green light, or if he drops something, or if something doesn't work properly and he needs to put extra effort into using it. Pretty much, imperfections in things REALLY digs under his skin, and one small thing may ruin his entire day. He tends to overreact and 'flip out' very easily.

He has extremely high anxiety, and suffers from tension in his muscles almost constantly because of it. He beats himself up over a lot of things, not literally of course. According to his parents, he's been this way his entire life, and no, it's never physical violence.

As much as it may seem that this type of behavior would lead to an abusive relationship, he actually respects, loves, and cares for me like no guy ever has in the past. He rarely ever gets upset with me, and tries extremely hard to calm himself & practice patience. He has made such significant improvement since before we were dating, but he still struggles so much with trying to gain control.

I'm hoping someone on here could give me a little advice about anger management. What should I, as his girlfriend, personally do to help him? What I mean by this is, what things should I do when he gets upset? What can I tell him?

I'd also like some information about anger management courses. What are the different options? What could he expect from it, and could I perhaps partake in them as well? Serious answers only please! Thanks so much !