Karol G knows a thing or two about breakups. And Romeo Santos is the go-to on making things get pretty sexy. On Thursday, the Colombian star released “X Si Volvemos,” the first single off her recently announced album. The song follows Karol and the bachata legend wondering what would happen if they returned with an ex.

“Let’s do it one last time, baby/Perhaps not in love but in bed we understand each other,” she sings in Spanish on the chorus. “It’s a porno, I love how we...