"Sometimes I guess there just aren't enough rocks." --Forrest Gump
I often compare the need to know to finding out you have a medical problem. Imagine that your doctor comes in and says "Okay, I'm going to prescribe a medication for you." What's the first thing you'll ask? What's wrong with me?
You can't wrap your head around a situation or try to recover until you know what you're recovering FROM.
Now imagine that you're already being treated for a particular medical problem. At a checkup, your doctor says, "Oh, by the way, we need to add another medication to your regimen." Aren't you going to want to know what has changed and what the new issue is? Of course you are!
Every time there is new information, it's like finding out all over again. Every time you find something out, you have to adjust to this new reality you've been presented with. The more new info that comes out, the more realities you have to adjust to, which often involves going through all the turmoil and hurt and anger all over again. This is why it's better for the WS to just spill it all out at once; you get it over with and there's nothing new for the BS to find out.
I've heard many WS say that if the BS knew everything, s/he would leave. The fact is, in your case specificially mysticpenguin, you ALREADY know enough to make you want to walk away. Yet for whatever reason you're still there, still trying. At this point I'm sure it's not like one more sexual encounter in the past is going to be the last straw... But the lying and hiding might.
The BS must know that they have all the facts. Again, you can't recover without knowing what you're recovering from. The BS deserves to know that the secrets are out in the open and the lies have stopped. As long as there's more to the story, I firmly believe the WS is not truly remorseful and/or is being selfish instead of committed to helping the BS heal.
My XWH is fond of saying that he has already hurt me enough and doesn't want me to hurt even more. That's great, but the fact is, I would rather hurt all at once than do it over months or years. I would rather just know what I'm facing so I can make a decision about it and move on somehow. And he darn sure doesn't get angry when I'm upset because he knows that makes it worse.
It's impossible for him to recall every detail - I know that. But as things come up, his best bet is to answer honestly no matter how hard it is. When you ask a question and he answers with the truth, it helps you trust him (1) not to do those things to you again and (2) to support you when you're struggling. For me personally, after a Q&A session where my XWH can respond without anger, I feel closer to him and happier than I was before. It's a major help as we struggle to R and one of the few reasons I'm sane enough to respond to this thread right now.
R Began 5/21/11
D-Day #2 7/9/13 (OW #2 is OW #1's first cousin)
R Began (again) 5/03/14