My Stepmom's Daughter is my Ex manga volume 1 features story by Kyosuke Kamishiro and art by Rei Kusakabe.

They’ve just broken up and become EX-boyfriend and EX-girlfriend, but now they have to live under…THE SAME ROOF!?Even though they still have feelings for each other, this EX-couple become SIBLINGS due to their parents' marriage!! Fall in love with a couple who constantly BICKER, but can't resist each other in this intensely-sweet and tantalizing romantic comedy!