I think my boyfriend likes my bestfriend.?

a few months ago i noticed my boyfriend spoke to my bestfriend more than me, he then started begging her to come out, he would stand at her door and not leave until he did, he used to tell me that it was so i would come out but most of the time i was stood there, he would inbox and text her and wake up her to talk to at all time's. Yet he never really spoke to me. My friends confronted him about it and he stopped but now he's started again, they did work experience in totally different places yet he met up with her to walk home. He planned to go to the cinema with some of our guy friends who i get along with really well as i've known them for years, he asked her to go and then when she said no he didn't ask me and my other bestfriend, he said he asked her for me but i don't understand why because she said no me and my other friend didn't get invited. He says its because my other bestfriend always say's no, but so does the one he asked, he also started making up loads of different things as to why, so i think he was trying to cover something up. He has now started deleting his inbox's on facebook but now we hardly speak and i just don't know what to do, I'm not sure if i trust him, i know my bestfriend's not intrested because she always say's no to going anywhere but if feel like things aren't going well anymore, but if i end it im scared our mutual friends might fall out with me because there mostly boys....