So my wife has had a bit of an epiphany:
Last week she was talking to an old friend of her's from high school days. He is currently going through something similar (ie. his wife cheated on him and now they are going through rather messy divorce). They spent a lot of time talking, and where Jenn wasn't listening to me when I said the same things, she did hear what he had to say. How much pain he was in, how he felt betrayed etc. etc. and in hearing him, she's realized what she'd done to me and the family. She also realized that for the two of us the root of our relationship has always been and still is strong (not the case for her friend).
I'm treating this with caution, it's a plus and I'm happy about it. There are other signs that things have suddenly started to improve as well. For a start we've had a couple of VERY good conversations about the cheating (no denials or hiding things) and the physical side of our relationship has come back. Plus there are the small things; spending time together (without the mobile phone) holding hands, quick hugs, bringing me a cup of tea unexpectedly.
All the same, I'm not assuming anything is fixed. She still cheated (even if she recognizes it was wrong) and we have to figure out the whys. Why she cheated, why she lied to me.
I guess the best news is that separation/divorce is no longer inevitable.
Keeping my fingers crossed!!!