Jammed, I wouldn't necessarily jump to the conclusion that W is gay. I dated a W for 5 years, while dating a M at the same time.
W I just loved, but the sex was more for her than me. I got very little out of that aspect, it was the emotional connection that I appreciated. M I loved and the sex was for me, if that makes sense.
I think Jung had a concept that everyone is neither 100% hetro or homosexual. Most people fall closer to the 20% or 80% line (obvious preference is what I'm getting at, not exact statistics).
It's quite possible that your W is not gay, just engaged in A that is an anomaly (sexual preference) for her, if that makes sense. As such, you shouldn't take it as an assault to your masculinity. I'd imagine you'd have similar feelings if W was w/OM?
This isn't meant to discount the pain that you are feeling. It sucks either way. But doubting yourself as a man, on top of everything else, is counter productive.
M & H: 40 M: 5.5 T: 7.5 OW: 7/09 Bomb: 9/09 Sep: 3/10 H files 7/10
