It's when two people can't get enough of each other, can't keep their hands off each other. - When they would do anything to be together, even forgo their currently relationships. Even if it's a boyfriend, husband, fiancé or friendship.
It's a relationship with no limits. A relationship that transcends social norms or understanding. One that will outlast time itself. Both people worship each other, almost blasphemously. Religion, Law, Moral Context, Age... nothing matters to True Lovers. Nothing can stop them.
2: They're completely insane, can't stop talking about one another. They get sad if they don't see each other every second of every minute of every day.
1: I know what you mean, they barely speak coherently anymore.
2: It's like they're addicted to each other, and need a daily fix.
3: They're true lovers. That doesn't happen every day.