If I want to apply for a fiancé visa for my Iranian boyfriend, what are the chances of this type of visa being banned and what are my options?

The President's ill-considered, unwise and Constitutionally suspect Executive Orders are not in force at the moment, but as you are aware there is ongoing appellate litigation and the ultimate outcome remains unclear. In the meantime, generally a U.S. citizen may petition for a foreign national to obtain a fiance visa to enable the foreign national to enter the U.S. in order to become married within the required time and in order to then be able to file an adjustment of status application in the Immediate Relative visa category. Another option may be to become married abroad and then proceed with Consular Processing. There are pros and cons to each approach, and of course there are many additional details that can determine eligibility. 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.