Every State in the US has different laws on divorces. I'm sure that England has specific laws. Having gone through a divorce 6 years ago after a long time marriage, I believe that I can speak with some authority.
The first thing is to get advice from a good lawyer that you trust--one who is familiar with divorce law. On what happens, I can only speak for Pennsylvania law. To differ with what Ericka said earlier, division of property in Pennsylvania is not 50/50. Pennsylvania law specifically states that "there will be an equitable distribution of property". Generally, this falls into the 50/50 category. In PA, the divorce is no-fault. The problems begin with property settlement. The property will be settled as to agreement by both parties. If a property settlement is not reached in a reasonable time--generally two years, either party may petition the court for a settlement. My lawyer advised me to work toward a settlement as he would never recommend that anyone go before a court. He said that you never know how a court settlement will go.
In Pennsylvania, all property owned by the husband and wife are considered marital property, regardless of how the property is titled; therefore all assets are considered.
Remember, there is no such thing as an amicable divorce. Once the lawyers get involved, things can get nasty.
So, you found her making copies of bank statements, financial records, etc. You start doing the same thing on her records. Be ready and prepared. Don't wait until a divorce is filed.
This can be a very stressful time. you must remain objective at all costs. You can't allow yourself to become emotional at any time. I have a good army buddy who has gone through two divorces. His advice to me on being objective was as follows: "Remember what it was like to call in artillery or an airstrike on a village. You can't be emotional. You can't think about how many people you are killing. You just have to call it in and kill them". I always kept that in mind. He was right. That is how I faced my divorce. Yes, I took a financial hit, but I came out of it standing on my feet.
Be prepared for the worst scenerio, get a good lawyer, and good luck.
Jodi