Why won't my gay boyfriend accept me for being straight?

Here's the deal. I have a gay boyfriend, but I am straight. I only date gay men and have relationships with them. A few weeks ago, we told my dad we were butt buddies and my dad tried to jump out the window. My boyfriend told me to come to terms with who I was, and I told him "Yes, I am a straight man...so straight in fact that I sleep with men because I love women too much"