My bf told me casually on Wednesday (via text) that he went to a board game cafe with my younger sister that day. This is a cafe that he and I have gone to many times together or with friends and/or my sister. They were good friends before we got together. I know in my heart that he wouldn't do anything, but my head keeps thinking over it saying, "yes, but what if" etc. And I work away from home during the week (until Oct 1st), that makes it all the more harder. I also recall my sister telling me and my Mum several years ago that she has a feeling he likes her - asking if they could hang out, seeming like he was pursuing her. Even though she had, (until recently), a bf. This is also the sister that made me the way I am (until getting with my bf) in regards to my low self-image. She used to bully me when we were younger. She would call me ugly and say that she was much prettier, smarter and skinnier than me. Having that told to you so much when you're young leaves massive mental scars. So although I feel more confident because of my bf, knowing that he's hung out with the very person who made me doubt everything about myself, it leads to overthinking. I didn't respond as I was about to go to sleep, and as I work as a nanny, I'm very busy, so didn't respond immediately the next day. Come yesterday evening, he had text me some more, so when I had finished working, I responded to his messages. I said, "oh.. that's nice for you", in regards to the message about going there with he...