Will he have a problem since he already had a petition before?

Generally, when a foreign national who entered the U.S. lawfully and with inspection has become married to a U.S. citizen, the couple may succeed in a marriage-based adjustment of status application process, and this is true even if the foreign national previously was married, initiated an immigration application process, and then became divorced. Note, however, in the new marriage-based case, the USCIS can be expected to scrutinize not only the current marriage, but also the previous marriage, to assure both were bona fide relationships and neither was entered for the purpose of fraudulently obtaining immigration benefits. For this reason, the newly married couple should be prepared to supply a strong and persuasive set of documentary evidence of the bona fide nature of both marriages. Exactly what will constitute a strong and persuasive set of documents is determined on a case-by-case basis, taking into account all of the relevant circumstances. Of course, there are many other details that determine immigration eligibility too. There really is no substitute for you and your fiance to consult with an immigration attorney who, after learning all of the relevant information, could advise about eligibilities, options and strategies to attain your goals, and who then could offer legal representation in the often complex application process.