Too many to list, so 3 suggestions. 1st is from the '60s but I didn't hear it 'til 2 years ago. 2nd is very recent. 3rd is classic bossa nova. All 3 are quite romantic (and blue):
Irma Thomas/"Anyone Who Knows What Love Is (Will Understand)"
https://www.youtube.com/watch?v=wPT4UizFUEY
Melody Gardot/"Sunset in Blue":
https://www.youtube.com/watch?v=qndrrfdmPIA&list=RDMM7_XiW7VrQSo&index=2
Astrid Gilberto/"How Insensitive" (even through translation, the words are beautiful & sad):
https://www.youtube.com/watch?v=XxVWqOdn150
Irma Thomas/"Anyone Who Knows What Love Is (Will Understand)"
https://www.youtube.com/watch?v=wPT4UizFUEY
Melody Gardot/"Sunset in Blue":
https://www.youtube.com/watch?v=qndrrfdmPIA&list=RDMM7_XiW7VrQSo&index=2
Astrid Gilberto/"How Insensitive" (even through translation, the words are beautiful & sad):
https://www.youtube.com/watch?v=XxVWqOdn150