Quote Originally Posted by Pamme64 View Post
I know that my perspective is different, but it comes from a place of having been cheated on. The thing that made me the angriest, and ruined friendships was that no one told me while it was happening. Believe me, if I had known, I would have left xH much sooner than I did!!. I would have loved to have that as an excuse to leave. So, when asked directly about stuff like this, I spill the beans. If the person is a good friend, I tell them without being asked. I think it is wrong to lie by omission about this sort of life changing information. It is a robbing of one's ability to make good decisions about one's life, because she only has half the information.

Obviously, the only thing I think you should do differently is tell her if she asks directly. She knows, she just needs confirmation. If FIL doesn't want to do the time, he shouldn't do the crime, and then essentially brag about it by dragging your partner, and by proxy you into it.
I agree with this.... those hiding the truth are really no better than the liar, especially if they're asked the question directly.