Thanks for your enquiry and am sorry to hear of your situation.
As a joint owner of the property, you are entitled to access your house as and when you wish. Therefore, if your wife were to change the locks, you have the legal right to use reasonable force in gaining access to it (ie by breaking a window for example).
I hope it wouldn't come to it, but if you fear such action may cause a full blown argument/fight, you should speak to your local Police station who may send a Police Officer to attend the property wen you gain entry if the Police feel that such an action may cause "a breach of the peace".
I hope this assists you and sets out the legal position.
If I have helped, please don't forget to rate my answer.
There is no legal need for any document to be drawn up in that you are free to come and go as you please. Therefore, any document drawn up stipulating what times you are allowed access is not really worth the paper it is written on. However, if you believe this would pacify your wife, please feel free to sign such a document.
As regards ***** ***** to the Police, I was implying that the Police would tell your wife "to calm down" and explain to her that you have a right of access to the property if they did attend on you entering the house.
I hope this helps.