Hi Op,
I feel it is very important to come together on the finances and not completly stop her from having any responsibilities, from my own experience i find it better when a couple operates together, you are having to move into a position of control here with the finances, you are now clued in and if you do have a joint account you can monitor it further, a joint account would symbolize a more team based relationship, when my BF did it with me i felt very included and respected,
I just feel you need to help her be open about dealing with finances and speaking to you about it, you dont want to be the man of the house you want to be a team, it is all out in the open now, no area of a relationship should be hidden, and there may have been a bit of denial in that on both your parts,
This could symbolize a new start on all accounts, excuse the pun!