Aside from the entirety of Crush? (Which is possibly the most romantic episode of any show past, present, or future, in this or any parallel dimension...) All the stalking, shrine-building, mannequin dressups, Harmony dressups, clothes stealing, building the freaking Buffy-Bot, kidnapping both Buffy and his ex-partner of many decades to sacrifice one before the other's eyes... You don't get romance running on higher octane than that. I can't even imagine it possible.
All of that says "creepy" to me, not romance lol