It's not so much what he would otherwise be doing in my opinion so much as it is sometimes, as a couple, you have to do things you don't want to do. When I have work functions, he doesn't want to go, but he does for me because it's what couples do for one another. When he has some friend with a party, I probably don't want to go but will agree to stop in with him for a little bit.
Relationships take involvement from both parties. I am a gamer, so I get the draw of it, but I would never not support my man if he wanted me to because I was busy gaming. Even if I'd really rather be gaming.
That said, I don't expect him to do every thing I have to do, but I don't think it's too much to ask him to come out to socialize once every couple of months.
Also, when I do go out with him when I don't really want to, I usually have a better time than I expect to!