My answer varies so much, especially reading all the previously made points.
I was 14 when my parents were finally divorced, separate households etc. i was not told any specifics, but then I didn't really question it - there had abeen a few yeas of constant fighting and coldness leading up to it. I would not have wanted to know something that specific though, as it stands i think both my parents had specific issues and share blame to the fall of their marriage.
What I wanted to know most honestly, was how it all affected me. All kids, even teens need to hear its not their fault and they are loved. Kids need to know, what does this mean as far as living situations, will they have to move, change schools, will their weekends be disrupted, etc. Kids want to know what will happen with holidays. Kids want to know if this will affect their parent's ability to pay for college, or driver's ed. Kids want to know if the annual family vacations will continue. Kids want the answers to a lot of questions - ones parents might not have the answers to right away. But regardless, the kids do have a right to know the stuff that affects them, even if at first its a "don't worry, we will make this as painless for you as possible", and if they are teens, maybe even be consulted on some things.
And I think once those kinds if issues are addressed, the kids will back off on asking too many questions about the specific relationship stuff; right now these teens have a million questions and concerns, probably more then they can even sort out or verbalize and sounds like their getting vague answers. The parent child relationship is a separate relationship then the spouse spouse relationship, and not every thing needs to be shared between them, and each relationship has its own quirks to be attended to.