We have always had a joint account. Never hid anything from each other and always place both our checks on the same checking account.

It wasn't until the past month in which I noticed she got a check card delivered to the house (by her mistake) and I noticed she had opened an account somewhere without letting me know. I ignored saying anything about it.

But this past check, she took 10% out in cash and deposited the rest, which we had never done. I am assuming is to place on that other account.
Do I just sit and brew over this and do nothing?

Me: 37, WAW 33, M 13 years
Kids: Boy: 4, Girl: 8
Separated: 10/24/13
DB since: 12/14/13
Big D talk started: 1/1/14 (Not served yet)
Still living together/Separate rooms