"I Stay in Love" is a song by American singer-songwriter Mariah Carey, taken from her eleventh studio album, E=MC² (2008). It was written by Carey, Bryan-Michael Cox, Adonis Shropshire and Kendrick Dean, and produced by the former two. "I Stay in Love" was released through Island Records on October 28, 2008, as the fourth and final single from the album. Drawing influence from the R&B music genre, the song features a piano and keyboard-driven melody, and a strong accompanying drum-beat. Lyrically, the song finds Carey getting "her cry on with the connect-the-dots break-up track." She describes the old time she shared with her love interest. She narrates that even though they said let go, and that she is aware that there is nothing left in their relationship, she still "stays in love with him".

"I Stay in Love" received generally positive reviews from music critics, with many considering the song a strong ballad and a highlight from the album, while complimenting its production and piano-driven melody, despite criticizing the similarities to Carey's previous single, "We Belong Together" (2005). The song performed weak commercially, becoming Carey's first single from the album to not chart on the US Billboard Hot 100, although peaking at number eighty-one on the Hot R&B/Hip-Hop Songs chart, and becoming Carey's fourteenth number one on the Hot Dance Club Play chart. In the United Kingdom, the song debuted and peaked at number ninety-five, and spent only one week on the UK Singles Chart.

Carey performed "I Stay in Love" live on two high-profile televised events. First, on November 8, 2008, she was featured as a guest judge and musical performer of the fifth season of the popular British talent competition, The X Factor. Additionally, Carey performed it live at the American Music Awards, held on November 23, 2008. The song's accompanying music video was filmed by Carey's husband, Nick Cannon, and features Carey as a dancer in a Las Vegas show at the Bellagio Hotel and Casino Resort. Additionally, during the show and its preparations, Carey realizes that her ex-lover has found love with one of her fellow dancers, leading her to blow up the car he gave her, as well as its accompaniments in the Mojave Desert.