How to have a successful affair: you don't.
Don't stop reading this. I understand why people suggest you should do something that you don't want to do, but that doesn't mean you should ignore their opinions. I just want to say that.
The way I see it, you could either tell your wife how you feel, try to endure, or, if you're fixed on having an affair, tell your wife that you want to.
Sounds stupid, but if ask your wife whether or not you can, she might either agree, saying sorry or some such thing, say no, or she might realize how much she's 'neglecting' you. I put that in inverted commas because she might have lost her sex drive. The point is, if she feels sorry for you, she might decide to give you what you want.
A final, slightly evil, possibility; don't tell her, but if you know enough about the internet, you can get a computer to access a non-existent server. That way she won't be able to play the game and, if she doesn't play the game for a while (from three days to three weeks), she'll lose the fixation.
Note: if you want to know about the techy side to this comment, just ask. I don't pretend to be an expert but i know a fair bit.