Megane Koushaku no Hatsukoi to Jimi Reijou no Kusare Kansatsu Nikki

In order to avoid the pressure to marry from his relatives and other ladies looking to take over the household, Duke Evald proposes a fake engagement with Lydia, the count's third daughter, in exchange for her debts. But, what the duke doesn't know is that she has a dark side: she is a "popular rose (BL) novelist" who observes Evald and fantasizes about BL stories. Her behavior is very different from that of other noble ladies, and gradually Evald becomes interested in Lydia...