Immigration Question- form 751?

You need to consult an immigration lawyer. If you are divorced, then you need to file a new I-751 and ask for a "good faith marriage" waiver. You cannot rely on the old joint I-751 (since you are no longer married). Even if your pending I-751 is approved without an interview (as it happens sometimes), you will be in a lot of trouble later on when applying for naturalization/citizenship.