This is stressing me out so much. I’m sexually active! And I don’t take birth control.

But sometimes after my period or sex, my vagina has this irritation feeling. I touch and it kinda burns. I be getting this frequently. I feel like it could be a yeast infection but this is happening frequently now. But they go away after a few days but always come back.. and this time my boyfriend told me it has a strong odor. But I honestly think I get this infections from him. How can I prevent from this “yeast infections” from happening.