I'm just tired of the evasiveness, of never feeling like I get the whole story, of always feeling like he's leaving out details just so he can control the information he gives me. Is that an alkie thing or something else?
Yiiiiikes. The evasiveness and cherry-picking facts to share does sound a lot like regular alcoholic behavior. But the story you relayed about the friend and the email reeks of a scary personality disorder. Seriously.
I'll say this once because I wish someone had said it to me back when I was wondering about my ex's emotional health. It's worthwhile to look further into NPD because it will help give you a frame of understanding and will suggest possible ways of dealing with your partner's bad behavior. Your ex sounds like my ex. My ex is NPD. It was confusing because I was always operating with incomplete information. He only did what was best for him. I kept trying to reason with him or find explanations and cures for the relationship. In hindsight, a lot of his controlling and evasive behavior was really creepy.
With my NPD ex (I'm confident using the label) I eventually had to adjust my expectations roundly, develop extremely strong boundaries, and rely on him for no information. I had to get rid of my fear of looking like a b**** or falling into his traps of guilt. The worst was when he would accuse me of completely false things -- he even had my mom believing in some of them -- and I got hooked into arguing about whether his lies were real or not. NPD's can't stand looking wrong, unimportant, or lesser-than. When you can recognize what that looks like, and you're able to see them with pity and not anger and disappointment, it's easy to interact with them strategically to get what you need (never expect them to fill your emotional needs).
Anyway.