Interesting question. My specialty is boardgames, but I have spent some time playing PC games, too. And some of my friends are definitely hardcore console gamers. My next-door neighbor is in his late '30s, and when he gets a new console game, he spends nearly 100% of his free time playing it for the first week after he gets it. So maybe I have some insight to offer.
With a few exceptions, most of my gamer friends are losers, at least by general society norms. They don't have good careers, and many of them didn't get a college degree. They either don't date, or they end up with unattractive geek girls. They don't buy houses, they don't get married, and they don't have kids. Some even still live with their parents. For all practical purposes, they are still boys, except that they have (low-paying) jobs. But when they play these games, they finally feel like winners. Within the tightly-controlled boundaries of a game, they can learn the rules and win the game. In theory, they could do the same in real life, but real life is less structured and less predictable. In a chicken-and-egg kind of way, it isn't clear if they are losers because they play games, or play games because they are losers, though I would lean towards the play games because they are losers scenario. Either way, they are kind of addicted to these games, because the games seem more rewarding and enjoyable than real life.
When I was younger, the games weren't very good, so only the most extreme geeks got addicted to them. But now we've got a lot of kids who are growing up with these games, and the superior graphics and challenging gameplay make them more addictive to a wider audience. Add in the internet, a big increase in science-fiction/fantasy/superhero movies (thanks to CGI), and weaker family structures, and now being an introverted nerd is more acceptable than ever before.
There are exceptions, of course. Some of my gaming friends are happily married, with kids and houses in the suburbs. And I've got a couple of gamer friends who are least successful in the workplace, though their personal relationships are lacking. My parents really encouraged me to be well-rounded, playing sports, joining Boy Scouts, and working a summer job every year starting at age 10, so I think I turned out okay as an adult.
Sorry, long rambling answer there. Anyway, your gamer dude is probably hooked, and not likely to change his ways. In his dysfunctional way, he probably does care for you, but he may never be able to meet your standards for proper boyfriend behavior. It doesn't make him a bad person, but you might be happier with somebody more normal.
Good decisions come from experience. Experience comes from bad decisions.