You all make good points.

Instead of that email that I drafted, I wrote another one where I basically ask her if we can have a new year’s resolution where we are completely honest and open with each other regarding what we are spending money on. I proposed that we write it down for each other to see and we will do so without judgment for January. At the end of the month, we can sit down and discuss where our money went and how we feel about it.
This is the core issue – the lack of communication and treating our money separately. We decided to do that long ago because she had a bankruptcy and did not want to ruin my credit, but I think that now that we have a family, it is time to start thinking differently. I hope that she will agree. I’ll send the email (both of us do better starting hard conversations in email partly because we don’t won’t to argue in front of the children). After the email, she will either reply back by email or talk to me in person. It will be okay because I was careful in how I worded things.
If we have trouble navigating through this, I will consult a couple counselor, but I am hoping that we can do it. My issue that I bring to this is that I hate conflict so I avoid these kinds of topics because I am afraid of how she will respond. But, if I can push through my fears and start the real discussion, then I am hoping that we can come to some conclusions together.
I think that I may look into getting the financial peace DVD. We are so incredibly busy that we would not have time to go and would not have anyone to watch our young kids anyway, but I think that she’d be willing to watch it with me.