Why is my spouse required to sign all the documents?

Under the Family Code, it is presumed that the property purchased by a married individual shall form part of the absolute community (or conjugal partnership if the spouses were married before August 3, 1987), unless the spouses have agreed to a separation of property before their marriage or if one of the spouses executes a sworn statement (Affidavit of Paraphernal/ Separate Property) stating that the funds used to purchase the property do not form part of their absolute community of property or conjugal partnership but were taken from the personal/paraphernal/separate funds of his/her spouse. Note that the Affidavit of Paraphernal/Separate Property must be duly notarized or consularized (if executed outside the Philippines).