<human>: As the title says, last night my boyfriend kissed one of his male friends at a party we were both at. I don't care if he's bisexual, but if he's dating me he shouldn't be kissing anybody else regardless of gender, but he doesn't see it that way. He described it as "lad bantz".

I also have a problem with his best friend- 17F- her and I have never got on, and he told me that whenever he's friends with her he can't help but really like her (they weren't really talking when he told me this) and they have a history together- not sure exactly what as he won't elaborate. I don't mind him being best friends with a girl, as my best friend is a boy so it would be hypocritical. I'm more worried about the comment he made and the fact that he's really secretive about when he's spending time with her, to the point where he lies to me about it and I find out through other people.

When I told him how I feel about their friendship- not looking for him to choose between us, I just wanted to be open about how I felt- he basically told me that I was being irrational and stupid. 

He also told me that when we have sex he thinks about other girls and I would have also thought that was nothing if it wasn't for the way he was acting when he told me that, like it was a really big secret and a big deal.

Could you distill the essence of the text into 1-3 sentences?
<bot>: I dont know if I can trust my boyfriend, he's secretive about a girl he "used" to have feelings for, and he kissed somebody at a party right in front of me and sees it as a non-issue.