Bacterial Vaginosis

I keep getting “recurring bv” and I don’t know what’s causing it... I’ve been having sex with the same person for a year and a half and he’s the only person I’ve ever had sex with (I’m not his first but I’m his only at the moment) I looked on the internet and it said that it could be anything like the soap I use, the underwear I wear, how often I shower and all that stuff🤷🏼‍♀️ I notice that it smells after I have sex but it just started in July 2019 and I’ve already cured it 3 times and got it again and it’s very annoying and kind of embarrassing..... I don’t know how to make it stop.