"Actually, you're the second person I love most."
She and I are secretly dating under a strictly confidential "second choice" arrangement...
My girlfriend and I each have our own one true love, our first crush. Even so, we're still a real couple. We meet in secret, go home together, and do things we can't tell anyone else about.
But a second choice is still a second choice. If we end up with our first loves, who love us back, our relationship will automatically come to an end. That's what we agreed on from the start.
But when my first love began to get jealous, my girlfriend came to me in tears...
"I'm sorry. I'm such an idiot. I'm falling more and more in love with you."