Boys' Love Novels Don't tempt me! Kadokawa Ruby Library

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He was told by his lover that he would break up with his wife for the reason of his marriage.
When his younger brother, Shunpei, came to tell him about his excessive treatment on behalf of his lover, he became enraged and said that Shunpei would replace his older brother, and for some reason he became half cohabiting together.
From housework to H, Shunpei, who came in contact with him as if he were a lover, was at the mercy of Tsumugi, but the wound of his broken love was gradually healed and Shunpei's attitude, which did not seem to be an obligation, started to shake his mind.
At that time, Tsumugi met Shunpei, who was Shunpei's older brother?
What would you do if you fell in love with Shunpei's younger brother? Step love starts from the contract of a substitute lover.