A fiancee that has entered the country, for immigration purposes, is not considered a resident. There is a residency process to apply for and go through when you are either engaged or married to a US citizen (for more info please refer to the immigration website for more info at USCIS.gov).
For our school purposes, he is! We consider him a resident because the international students at our school are F-1 visa holders, and we manage their SEVIS records directly. Students with other USCIS processes who do not hold an I-20 therefore fall under the “resident” category as we do not oversee the maintenance of their status.