Boyfriend outed me

So Im bisexual have been since I could remember and before 5 years ago I dated a girl, and we broke up I started dating my boyfriend. We have been together for 4 years and Im very close with his family but I havent told them I was bi because of how I know people react. They are accepting if the LGBTQ community but they are the type to feel uncomfortable in a bikini around me or something so I just never told them. Well recently I was talking with my boyfriend and his sister and I was telling story about my ex girlfriend but I told her it was my bestfriend, my boyfriend jumps in and tells her "It was her ex girlfriend they used to date for a while" and I swept it under the rug and said oh it was just a thing we kissed once I was young. I was so hurt and embarrassed. It was about a week ago and I still keep thinking about it, I told him it upset me and he apologized and said he thought I told them. Ugh Idk how would you feel?