should I tell him?

I know I'll get a lot of criticism for this but here goes. I'm bisexual and so is my best friend. My boyfriend is okay with it but says that I'm not allowed to do anything with a girl unless he's involved. Well I went to sleepover at my best friends house and we got really messed up and we were kissing. Her husband was there but he's okay with it completely. All we did was kiss. Should I tell my boyfriend about it? Or leave it alone?