Your story really hit home. In fact, I'm having trouble putting my thoughts down here.....our situations are VERY similar. There's a question for you at the bottom.
My W pulled away too. Overnight she went from stay at home mom to career women, stopped wearing her wedding rings, dropped her friends, and was consumed by her exciting job. I supported her, including cutting back about 15 hours from my work schedule to care for the kids - I did understand why she wanted to return to work, I just wish she'd figured that out before pushing for another kid. Our very busy family life went off the tracks. I was right about one thing - having three kids and two careers is a constant struggle. I love my 3 sons but every single morning is a tense negotiation about who takes who where. My career has taken a real hit, which is embarrassing since we work at the same place. I felt like she was leaving because she DID leave. She completely pulled away from me. Just like I knew she really would want to go back to work soon, I know what this pulling away really was.
W's boss is totally into her, and she knows it. She has never once rebuffed him (that I know of), not even a simple gesture that would tell him the advances are unwanted. When she has meetings with him she dresses up - boots, skirts, little tops. The work relationship is perfect cover for them to feel each other out......did I mention I work at a college? and this OM could be considered her "mentor"? Something about academia makes people think that the usual office boundaries don't apply. No one sets a professional tone. (By the way, I hope your Ws former mentor gets a little karma)
My W wants a strong, confident man and that's too bad - because she HAD one and she worked him to death and torn him down. Harrier, it got back and when I couldn't do anymore we had OR talks and I came up weak. My W was convinced I had GAD or panic attacks - and for awhile I thought she was right. I totally agree with the DBing principle of "working on ourselves" but sometimes I think the missing ingredient to build a strong H is the undeniable love of his W.
You said you had a lot of deep conversations with your W. Do you mind sharing how you did that without it going wrong? My W does not do feelings, want to talk about the past or the future - it is almost physically painful for her. She twice said no to couples therapy. I REALLY think we need to have one of those painful talks - we never seem to get to the real issues - but every other conversation we've had ends with me looking really bad. She simply can not accept that she did anything to contribute to our situation.