The most obvious piece of evidence is the ring, which is diamond and a heart, but the snippet gives more clues. The lyrics around the whole "Do you have a girlfriend" part do seem very adulterous, with this as more proof Taylor's done it before http://www.dailymail.co.uk/news/article-2968919/Ultimate-betrayal-Taylor-Kinney-s-girlfriend-woke-late-night-call-heard-kissing-sounds-breathy-whispers-man-cheating-woman-Lady-Gaga.html It's obvious Joanne was influenced by their split, and