您好。我的未婚夫正在給我申請K1簽證。但是他最近發現我到美國後,如果他給我申請綠卡,他必須簽署一個Affidavit.下面是他給我的內容"The Affidavit of Support is a long term commitment by all who sign it. It is legally enforceable by the U.S. government for any means-tested public benefits utilized by the sponsored foreign spouse. The obligation to support the foreign spouse ends when the foreign spouse becomes a United States citizen, has earned 40 work quarters (equivalent to approximately 10 years of working), dies, or permanently leaves the United States." 他說如果我結婚後和他離婚,10年的責任對他風險太大,他不想簽這樣一份東西。我想問是每一個想給他們的中國妻子辦綠卡的美國人都要簽這個嗎?