is bacterial vaginosis an std

My fiancé found a prescription bottle of antibiotics for bacterial vaginosis that I took back in January. he read online that it is caused by having multiple sex partners 🤦‍♀️ I’ve only been with him and one other person, which was at least 5 months before I was prescribed those antibiotics. now he thinks I cheated in January because he thinks bacterial vaginosis is an std ugh