The first part of the group's 4th album has the title song "My Heart is Fluttering", a song produced, composed, and written by member Kim Young Woo. It talks about the fluttering heart of a man falling in love. Busker Busker's producer Kim Ji Soo participated in editing the song.

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All of the songs in the album were worked on by the members themselves. Their label said, "Sweet Sorrow put all their efforts into the details of this album, including composing, writing lyrics, and even producing. We hope that music fans can fill up their emotions with their 4th album part 1 'For Lovers Only', an album where you can see the members' musical ambitions. Please show a lot of support to Sweet Sorrow's new album."

UPDATE: Sweet Sorrow has also released a MV for "Pounding Heart".