I have a document that was drawn up by my husband's ex-wife and I would like to know if it is legal. The document is an addendum to their separation agreement, which they used as their divorce decree. In this document it states that we are to pay her $200 a month until 08/2009 for medical expenses and the document was signed by both parties. I was told that anytime you have a legal document to add as a modification to an already standing legal document that it needs to be witnessed by 2 witnesses one for each party then the document would need to be notarized. This document has the same witness for both and was not notarized. Is this document legal?