Stewart wrote this love song when he was dating the Swedish actress Britt Ekland; they were together from 1975-1977. Stewart said, "It wasn't totally about Britt... it could of been anybody I met in that period - and there were a lot of them."
This statement may have been influenced by the $12.5 million lawsuit Ekland filed against Stewart, in which her lawyers pointed out how she inspired some of Stewart's most successful music.
Stewart and Ekland split up very publicly after he was photographed leaving a nightclub with another actress, Liz Treadwell. In his autobiography, Stewart said that Ekland thought they were going to get married, but he had no intention of settling down and in turn, was unfaithful.
The songs Stewart wrote for the Foot Loose And Fancy Free album deal with this relationship, and are rather conflicted. On "You Got A Nerve" he is quite hostile; "I Was Only Joking" finds him dismissing his lover. "You're In My Heart," however, is the kind of song that would make a woman believe that Stewart is smitten and in it for the long haul.
Soon after the album came out, Stewart explained to NME that in writing the songs, he was expressing his true feelings, and that it made him realize that he wanted to be free, as suggested in the album title. "The songs came first," he said. "I didn't actually think, 'Well, I'll put it in the songs and hope she hears them and knows what I mean.' But it's ironic that the album title and the songs came out as they did."