Almost giving up on finding a song

I've been searching for a song for two years now and I can't find it.

It was an emo band I think, and it was a male band but they collaborated with a female artist, probably Hayley Williams or similar.
The Lyrics I remember are

Female : "Do you remember the day we met"
(the male sings a line)
Female : "Do you remember a thing at all?"
(and then the male sings about lying together under the stars until morning)

Heard it in mid-2010 to early 2011

The first line of lyrics is also in a song called "Sea of Love" which has been covered numerous times by numerous different artists.