AIO My boyfriend does not trust me

Recently traveled with my family, before we left I started to feel like I might have a yeast infection. A bit of background in the situation, my boyfriend has never actually trusted me (his words not mine) I’ve never cheated on him we’ve had our fights obviously as everyone does and have had trust issues with each other his much more than my own, but after so long he still acts the same and I try to tell him exactly what’s going on. Although I do get upset when he is still upset after I explain it to him. Anyways I explained to him that I know my own body and that’s how I came to the conclusion I had a yeast infection and afterwards he proceeded to make a comment along the lines of “I just don’t understand how that happens” to me that insinuates that I had to be doing something out of the regular or weird to cause it and I not so nicely told him that I am a women and will get things like this even with the best hygiene ever. I guess I just would like to know if I’m being overly irritated about it (some other background is there is multiple times a month if not a week that things like this happens and he says things that insinuate that I am acting out of the ordinary etc.) how can I change the way I react when I know I’m not doing anything but he refuses to believe that or how can I be more comforting and nurturing towards him in these situations?