Hello Cote,
Having followed the whole thread I delayed adding my own story but feel it may be helpful at this juncture.
That said - my post isn't so thought out that it may have huge holes in the logic. Apologies - I want to help not me,me,me IYSWIM. I am new to MN so this long winded post might not meet with etiquette (appreciate a steer if not).
Whenwill - I agree with your last para - but, unfortunately, it presupposes that both parties have similar esteem/moral code. It would appear that Cote's DH is already at a point of secrecy/denial which (read mine) that doesn't then respond to honesty.
Of course hindsight has amazing powers of perception. So...
January 09 whilst looking for other stuff in my exP email (we had open access to each others accounts... helpful for holiday info etc) I came across a looong thread by an unknown woman at work. I read them. I was concerned as it seemed clear she was building up to a pass and his replies, whilst not a green light, weren't discouraging. I chose to do nothing thinking I didn't want to be his moral gatekeeper (and I had DS, 2yo at the time, and DD, 5 months). A few days in I asked a mutual friend if she knew of woman X. She blanched. I became concerned and she said it was well known X was keen to the point of obsession on exP. I guess this got back to exP as I received an email from him saying: he was hurt I was saying he was having an affair and the the thing most likely to make him have one was being accused of doing so.
The posts here make it clearer to me what was happening - as I was saying I had at no point made such an accusation but was upset by the secrecy - ie the secrecy is stage one of a non-viable relationship. Anyway...
I looked again at the email thread a few days in. There was several from her unanswered by him then a drunken: oh-how-humiliating-sorry-sorry-I'll-stop-then type message from her and nothing further. (I now know this was staged for my benefit and they had an affair and set up a secret account to maintain it).
Jump back may last year (me forgetting these emails) and I ask him to consider marriage (as we have DS and now DD) and am told: No, as he no longer loves me.
FF a year. Include some Relate...it is my fault - I got fat - I was cross - resentful - aggressive etc. He tries again for 2 months (after I said OK Relate going nowhere lets start to dismantle house, finances etc). From November on he becomes distant, flinches from any contact with me. Goes away to NY on business (doesn't leave flight or hotel) then returns the same. A random day I pull myself up and choose to ask if he has something to say. He replies: Yes it isn't working, it never will. So I ask him to leave. (Jan this year).
FF a few painful months of new single motherness, sadness, could I have done more, been more etc, getting used to his access visits, he uses my computer and leaves email account open. I had a few seconds to read before he came upstairs from putting DS and DD to bed.
Enough to see 100s of emails from OW and a holiday with both names.
I confront him. He still denies it until I spin round computer and point out the plane ticket with their names on. Then he says he got together only recently, pure coincidence it is her, and for my benefit chose not to say.
From what I have read it seems unusual to not come clean when the affair is exposed but I wanted to share as I didn't consider the need for hard evidence and didn't have it (until the second time he left his email open last Sunday) as I couldn't quite believe one could deny ad infinitum.
This time I could read at leisure as he had finished his visit. He packed and left our house in the morning and contacted OW that afternoon on the main account (the signal that I had taken the bait (of bad behaviour) and said go.) He moved in 2 weeks later. He spent his trip to NY buying OW xmas presents (we bought each other token books due to ££).
The most galling thing in all of this is that he continues to maintain NOTHING UNTOWARD HAPPENED. He planned a secret dalliance until enough time had passed so he could unveil her as a new P to the world (ie his integrity intact) whilst letting me be the scape goat and my behaviour explained as untenable to live with and continuing jealous sour grapes.
I have yet to decide what to do with my hard copy evidence (as still seems part of my newly devised (by him) madness to show family/friends xeroxed emails)
I guess I am already on the dark side
IIWY - I would use PI but if it came back as innocent I would tell him that was what I had done and the reasons why and maybe use Relate or similar to get to the stage Whenwill describes.
Then I think about the only other people I love - DS and DD - and how I would approach a problem with them IYSWIM and I falter. Or is it not comparable?