My friend invited me to join her choir. I was nervous as I know her best friend goes to the choir and is jealous of our friendship. Still my friend said it would be fine and so I've given it a go. But BF was totally weird, didn't speak to me, only spoke to friend and made me feel invisible. It was like she was staking her claim. I enjoy the choir but I don't think I want to go if this is how it's going to be. So AIBU to stop going and what do I tell friend?