Listen to Justin Bieber's new song 'All That Matters' What's a king bed without a queen? That's the question Justin Bieber poses in "All That Matters," a new song the teen-pop superstar released online late Sunday. The second installment in Bieber's so-called Music Mondays series -- in which he's promising to release 10 new tracks over 2½ months -- "All That Matters" follows last week's "Heartbreaker," which like the new song features less production than we're accustomed to hearing from the singer. This time he rides a bluesy guitar figure and a stuttering drum beat, and that's about it. And like "Heartbreaker," "All That Matters" is sure to spark speculation that Bieber is using his music to address his on-again/off-again girlfriend, Selena Gomez. "I'm grateful for your existence, faithful no matter the distance," he sings, "You're the only girl I see, from the bottom of my heart, please believe." On his website, Bieber wrote, "The lyrics of this song are pretty self-explanatory," adding that "when you fall in love with someone, that someone can make you feel whole." The tune, he said, "conveys that being in love is one of the greatest feelings on earth" -- but that "the void you feel when that love goes away is gut-wrenching." Word to that, Biebs. Listen to "All That Matters" below.