How do I tell him?

So I went to the doctor and they gave me antibiotics and the antibiotics gave me a yeast infection. This is my first time really having a yeast infection I never really get them so it’s pretty uncomfortable itchy and hurts. I know clearly I can’t have sex until I’m finish the antibiotics and now since I have a yeast infection im taking monistat the 7 day one. The thing is idk how to tell my SO that I have it without him thinking I have something. When we first met he said he ALWAYS wears condoms. He was in a 5 year relationship and he always used them. When his ex asked why they always use them he said he just doesn’t want to get anything which I understand fully. Not sure if by At least he isn’t a dirty kid lmao.. well we use them 24/7 once it did break though but he didn’t freak out or anything. But he just thinks anything could trigger a std or something and he goes to get tested often. One time he came into my room and it’s common for girls to get uti yeast infection etc and he asks me “ why do you have these gummies” it was cranberry gummies to help prevent uti. I was explaining to him that it’s common and girls get them and he looked and joked and said “ you have something that’s why” and I’m like wtf so I didn’t get mad bc I know I don’t I get checked also and he laughs and said he’s joking. I feel like I can’t tell him anything bc he will think it’s an std which is childish.. and most guys don’t understand these things. Don’t understand half the things females go through.. how do I tell him I cant have sex with him until I’m finish taking everything and are clear?