Most newlyweds wouldn't want their spouse working during their honeymoon, but when your job is writing songs, and you're inspired to write one about two people coming together, you get some slack. Bono started writing this when he was on his honeymoon in the Caribbean. He married Alison Stewart, who he had been dating since 1975, on August 21, 1982 in Ireland.
An early U2 song, this was the second single from their third album, War. Bruce Springsteen had already done the "Two Hearts" thing, but U2 did get to theirs before Phil Collins.
Bono said that in writing this song, he was hoping to create something that Aretha Franklin or Barbra Streisand would cover.
U2 made a video for this song with Meiert Avis, who directed most of their early videos. This was before the band got into concept videos - they were typically seen performing outdoors. In this one, they're in Paris. Mixed in with their performance are shots of street performers and of 9-year-old Peter Rowen, who appears on the album covers for Boy and War.