You've been in love before. It didn't last. It never does.
5 seconds sound clip from the Invasion of the Body Snatchers (1956) movie soundboard.
You can hear this line at 01:00:41.092 in the Blu-ray version of the movie.
Quote context
[...]
- Exactly.
- We're not the last humans left. They'll destroy you.
- Tomorrow you won't want them to. Tomorrow you'll be one of us.
- I love Becky. Tomorrow, will I feel the same?
- No emotion? Then you have no feelings. Only the instinct to survive.
- You can't love or be loved, am I right?
- You say it as if it were terrible. Believe me, it isn't.
- You've been in love before. It didn't last. It never does.
- Love, desire, ambition, faith... without them, life's so simple, believe me.
- I don't want any part of it.
- You're forgetting something, Miles.
[...]