Can I suggest that some of you dudes read Franco Seduction? (Not the Franco from these boards).
The theme is pretty simple. Women want to select the best possible mate, so that their genes get passed on to future generations (if they make an incorrect mating decision they will have lower quality offspring who are less likely to pass on their genes, thus the female trait of selecting the best possible mate is selected for). So they need to mate with a strong man. One of the ways they do this is by letting the man initiate sex. Weak men don't initiate sex, so by waiting for the man to initiate sex, she avoids getting pregnant to a weak man. Obviously, her attraction system is inherited through millenia of natural selection during which time condoms and birth control weren't available, so it basically assumes that sex = reproduction. Her instinctive behaviour is quite predictable like this. Note that if you're in an escalation situation and you verbally escalate like "I really like you, I want relationship with you" it's a disaster, this looks extremely weak.
So, I'm talking to OP (Account3275) and HellAtlantic -- based on your posts, you've both spent significant time with colleagues with significant amounts of attraction, possibly mutual attraction, and/or sexual tension -- yet you haven't made a move. This is why sex hasn't happened. Had you made a move, then you might have found sex wasn't on the cards. But more than likely, especially if you were practiced in seduction techniques such as handling women's tests (we are NOT having sex! I have my period! I don't have one night stands! I'm married! I won't go into a hotel, I know what happens there! et cetera)... you would have found she was down to fuck. Women are water. By assuming that many problems stand in the way (her boyfriend... her career... her social status at work... etc), you basically acted like her girlfriend, and she picked this up from you and ran with it. That's how a weak man behaves. A strong man just grabs what he wants.
As to OP, I suggest you read
this article. It seems to fit your situation. However, it does also appear, that she may be giving you a second chance. This almost never happens in cases of missed window, but it is possible. One thing we sometimes see is, you disqualify yourself as a lover, but still have significant boyfriend value. This doesn't seem to fit your case since she's married, but maybe she's considering leaving the marriage? More likely I would say, is that after missed window she acts as if everything is fine and she doesn't hate you, but really she does. She just can't admit that anything changed, because that would be admitting she acted like a slut. So she just pretends everything's fine, but strangely seems to throw up a lot of roadblocks in your way at every turn. That's typical missed window behaviour. Another possibility is what radeng suggested -- she never saw you as a sexual option in the first place, so no missed window is involved, the anger was because you tried to move things forward with her, and now she misses her bff?
Ray