Ok Chatter, it's not about the W, it's about Bill at this point.
The most important thing is that you, Bill, feel raedy and able to go through this next stage of the process and to be as self-focussed as possible. I think the most important thing is to work through that resentment from now. Even if the D does happen, that might continue to linger and you definitely do not want that.
I have a friend who has been divorced for 5 years now and her resentment has just made her blind (in a figurative sense) and bitter. As a woman, she will internalise, but as a man you it could manifest more externally. So, work to free yourself of the resentment.
My guess is that she is going to come running back. You guys don't exhibit the classic hatred that usually accompanies divorce, so I think there is still some chance here...but it will be on your terms, or ideally - with MUTUAL terms.
I think that's the aim here actually - MUTUAL respect.
About the UK, yes it's a fault-finding system (I've since learned as I conducted my just in case research), and ideally the reason will not go contested. Most solicitors will advise their clients not to contest the fault (ie Adultery or Unreasonable Behaviour).
For adultery - you would need to provide proof. In this case, her own admission would be acceptable.
Where things start getting heated is around custody and finance - which is why solicitors will advise clients to not contest the reason as it's a waste of time and money.