Is it considered cheating that I 18F flirted with my female best friend 18F?

I 18F have been dating my boyfriend 18M for around 6 months, I have this female friend 18F that I’ve known for around 8 years, so when we go out together with my best friend we joke and play sexually. My boyfriend considers it cheating since we touch other but it’s not really touching? We were just joking about our boob sizes and feeling it on top of our coats. She is bisexual, she likes girls but not in a dating way she just likes them sexually, however she likes men more and has a boyfriend, and I’m straight but neither of us are romantically attracted to each other. We joke around a lot with each other and i’ve known her for years before I met my boyfriend, so is it considered cheating? Or is he being a bit dramatic?