I agree with Groov. I am really sorry that you saw this - that's very hurtful.
But take a deep breath. Take five big steps back. And when your emotions have calmed a bit, think about whether this is going to change what you are doing. What difference do these emails make? You still need to GAL for YOU. You still need to work on you and become the person you want to be.
You might want to think about setting boundaries.
But please, do NOT tell W that you saw these emails.
What she says or feels today could be completely different next week, next month, or next year. Who knows. Also, it's hard to believe that what you read in the emails is 100% the truth . . . why is are you two going to a holiday party together, and staying over in a hotel? She still sounds confused to me. But do you think she is going to tell that to OM?
me: 44 XH: 42 M 11 years D10 and S8 Bomb drop 9/27/13 D final 7/1/14