Remarrying Someone You Had Previously Married?

If a man and woman get divorced, the woman gets saved, and neither of them has remarried, would it be ok if they got married again? Or, does the Lord even recognize their divorce to begin with? Are they fornicating if they are intimate with each other prior to being remarried?

The original question, “I became a born again Christian about two months ago on June 30th! I have repented and accepted Jesus Christ as my personal Lord and Savior! I have a question on whether something in my life is a sin or not? I truly want to live my life for God and I know I will never be perfect and make mistakes from time to time, however, I don’t want to openly and knowingly live in sin! So I really need your honest opinion so that I can live worthily before Gods eyes! Anyways I am divorced and have been legal for several years. However, my ex-husband and I have recently reconciled. We are not remarried yet though! We have a past and we obviously want to be intimate with each other! But my question is are we committing the sin of fornication? Neither of us has ever remarried anybody else. Please help and thank you in advance!”