I went through two plus years of this very thing. My wife plays online games and it grew out of her feelings of depression and suicide. Althought I hated all that was shared between them, the blessing was that it kept my wife alive. She told me of how she had planned it out. Locking the bedroom door with a note on it to keep our daughter from finding her. But their friendship brought her out of it, only to push her into something else.
It caused me to do and respond in ways i never would have. Listening at the door when there were on the phone and reading her emails to and from him. I became jealousy with anger and rage that it scared even me. But I loved her and poured my love on her daily inspite of it all.
It wasn't until last year when I demanded a divorce that my wife began to do and respond differently. Like less time on her game, more time with the kids, cooking, reading a book, spending time with her family and me.
And though I may be criticized for "taking it" I did learn much about myself and I see it as another tool toward helping others.