Your girlfriend is convinced that you are bisexual. So convinced that when you tell her you’re straight as can be, she gets exasperated. And she won’t let the issue drop. She’s always bringing it up, always insisting that she’s right, or that you’re so deep in denial you’re actually gay but simply refuse to acknowledge it. You’d break up with her, but...well, she’s curvy and hot. And sex with her is amazing. So you don’t mind too much until she issues an ultimatum: no more sex with her until you admit you’re a big fucking bi-faggot and start acting like it.