Ah yes, this is the great difference between how man thinks compared to how a woman does. I get what you're saying and what you wanted from him, I've even had the same kinda fights within my own relationship. If this guy is similar to my own bf, he most likely never needed much interaction at all to feel satisfied. When men go through depression, they can be irritable, and withdraw into themselves. And yeah, going out with friends may be just what he needed as with you he has to connect with his emotions, something that can be stressful when he is depressed. With friends, it's less one-on-one and he doesn't have to reach within himself to be social. This is the sort of insight I've gained from my own bf, after many long conversations (and arguments). When they are down, they can well appear selfish and isolate themselves and this is so hard for the partner, I know.
Yeah, LDRs are very difficult if both partners are not pulling their weight. You needed his attention and he was not giving you what you needed. The problem is also that men often don't understand, as they need to talk much less than a woman needs to. One of the main problems with LDRs is that typically (ofc there are always exceptions) men tend to find it easier to show love/affection through touch rather than talk (and women do need both, but touch less so). He doesn't really understand you and your needs, as his romantic/intimacy needs are different. It's hard to say exactly what he is feeling now, in his head he may be believing that you were too needy, caused too much drama etc (when it's more a mismatch of needs/expectations between you).
In your position, I think I'd be too hurt to try to continue the relationship after he found someone else, but if you feel deep down that he is who you want, I'd suggest maybe sending him a message. Explain why you acted why you did, how it can be different next time round and how you feel for him. I'd suggest an email/fb message rather than talking to him directly, this'll allow him to spend time and think on it at length rather than feel he's been put on the spot. Ask him to contact you once he decides, and leave the ball in his court. If he loves you enough, he won't resist trying again but if you get no reply, you know it's time to try and move on.