Confused

I've been with my boyfriend for a year now and we've known each other our whole life. Well we were drinking along with his guy friend and eventually he ended up saying he used to have a crush in my sister when we were teens. And his friend said the same thing and agreed ,they said it bluntly but were in our early twenties now. My question is should I feel upset about it ? Because i do. I feel like that was disrespectful but I could be over reacting. How would you guys feel?