My sexuality ft my boyfriend

For some reason my boyfriend gets really offended when I talk about girls because he knows I'm bisexual, but that doesn't mean everyone I talk about I'm undressing with my eyes! I've talked about it with him and we've come to an "agreement" but he still bugs. He watches porn, so do i, but why does it bother him so much if I watch lesbian? I'm sure I'm not the only person that does it. But I get it, I'm not straight but he still shouldn't feel insecure about me being with him. I love him and I don't want to lose him but I don't like how he jumps to assume I want girls and fantasize about them while I'm with him.