Work, social life, significant other, exercise, domestic responsibilities, etc. all take up a lot of time and are more important than gaming. I probably don't spend more than an hour or two a week playing games now which has resulted in a large backlog that I know I'll never get through... oh well.
I am the same way. I would like to spend more time gaming but life has other things more pressing to me.
I remember right before my daughter was born I had a WoW addiction. I was playing for about 6 hours a night and losing sleep. I was seriously hurting my body.
I got wise after I passed out one day and I gave up WoW cold turkey.
I used to love play multiplayer games too. However, I also found they cause me a lot of undo stress and tension in my life.
Now, the only multiplayer games I play are co-op games but the last one like that I played was the small one with aliens that Steam/Valve was pushing a few years ago (Alien Swarm?).
I have even gave up on consoles altogether. Last console was the PS2.
Now I only play one player games that are on sale on Steam. Usually that means I am 3 years late to the party and usually backlogged on games. I do not have to worry about pre-teens, angry game nerds who take gaming too seriously, or having to get to a certain point to make it worth while. I just play my 30 minutes of Fallout New Vegas right now, take my shower and off to bed.