Advice

So my best friend in the past has snapchatted my boyfriend always flirting and showing a bit too much skin. He didnt think anything of it I guess but I told them both it bothered me so they stopped. Just the other day she snapchatted him and said hey I wanna talk so that you'll be on my best friend list. So he snapped her he said back and forth that day, but it really makes me nervous and I feel like its gonna cycle over again. I'll admit jealousy is a bad quality I have, but I cant help feeling like it isnt really fair to me that they're both stepping over boundaries. What should I do? Am I beingdramatic, should I be fine with them snapping even tho she sends him things imnnot ok with?