Songfacts®:

• This song is about one of those breakups that gets really acrimonious, resulting in a mutually assured destruction. Pet Shop Boys lead singer Neil Tennant wrote the lyric about a real couple he knew that caught each other cheating, then seemed set on destroying each other to exact revenge. Most of the details are true, including the lines:
  
  We've both given up smoking 'cause it's fatal
  so whose matches are those?
  
  "There were these matches by the bed and neither of them smoked," Tennant explained to Q magazine. "Oh dear!"
• The sexual innuendo in "So Hard" is purely intentional. In fact, to promote the single, their record company sent out boxer shorts with "It's hard... so hard" printed on them.
• In the UK, "So Hard" was the second single from Pet Shop Boys' fourth album, Behaviour, following "Being Boring." It was a hit there, climbing to #4 to continue a run of hits from their previous album, Introspective, that includes "It's Alright" and "Domino Dancing." In America, where the duo are best know for their 1984 hit "West End Girls," "Being Boring" wasn't released as a single but "So Hard" was and reached #62.
• In the line, "I go one better - I'm indebted to a contact magazine," a contact magazine was a kind of magazine in the UK where people would place personal ads looking for (often intimate) companionship. According to Neil Tennant, this is one detail in the song that isn't based on the couple he knew.
• Neil Tennant took some creative liberties with the rhyme structure in these lines:
  
  I'm always hoping you'll be faithful
  ...
  We've both given up smoking 'cause it's fatal
  
  "I love that rhyme between 'faithful' and 'fatal' because strictly speaking those two words shouldn't rhyme," he said.
• The black-and-white video, directed by Eric Watson, was shot around Newcastle and North Tyneside, England, and portrays Neil Tennant and Chris Lowe of Pet Shop Boys as impassive observers of the kind of dysfunctional relationships described in the song. One of stars is Anna Gascoigne, sister of footballer Paul Gascoigne.