Romanized: Sugita ai no natsukashisa Literally: Nostalgia for a love that has passed
The Japanese already implies (although it doesn't actually _guarantee_) that it's "my" love that has passed, so I couldn't get the "my" in here without making it sound unnatural...ó_ò
If it's about the _man_ she loved (i.e. the "my love" is an allusion to him), then it would be æ„›ã—ã¦ã„ãŸå½¼ã¯æ‡ã‹ã—ã„ Romanized: Ai shite ita kare wa natsukashii Literally: I'm nostalgic for the man I loved
(I translated it from the remarks indicating the literal meaning, under the French translation.)