A question for the ladies please..

Hello ladies, I hope you don't mind me popping in but I would like to hack into the mind of a woman if you would be so kind.

My wife and I are currently going through some difficuilties which I have discussed in my previous thread - basically she has got caught up in a fantasy with another man, sending him pictures upon request and doing all the dirty chat. She has been a fan of the fifty shades trilogy and likes the Karen Rose books - and her explanation is that it felt as if she was carrying on with her own private interactive novel.

I do believe that this was an online only deal as the other guy is much older, and is in a lot of the celebrity social circles (he has 50000 or so followers on Twitter), that combined with my wife's 4 month pregnancy bump and our other son to cart around I'm obliged to believe her.
I work away a lot and so I have been partly blamed for my absences, leaving her seeking attention online.

When we are together we have a very healthy active relationship - I sometimes felt that she was carrying out antics from her literature as she is very creative, but I could keep up and it is never dull.

The frequencies of our physical relationship goes up and down with her libido, she blames the pregnancy and I am clever enough not to argue with a pregnant woman. I am now however slightly concerned that she may have carried out fantasies on me, that she got excited and turned on from by talking to this other guy.

I am having trouble communicating with her as she can't explain - this I understand. We are waiting for counselling referral but in the mean time I have asked her to try to write down how she feels and what we need to do to work on things.

So my question for you all is whether to you, this would have felt like infidelity? I have discussed this with some of my nearest and dearest, to explain and understand my behaviour, and all the feedback I have got is that it is cheating and I got similar here on TAM.

I did however have 1 lady colleague whom I confided in and she is adamant that it wasn't cheating, and was just a misjudgment on the boundaries of our trust. She now lives alone and has been hurt by her ex-husband, and considering that she has met my wife I do value her opinion.

I am not trying to get an army of references saying she cheated, quite the opposite actually. She's finding it very hard to talk and her family don't talk to each other about their problems.