Can't Tell Them Apart

Just writing for fun and trying to submit a short story. Under 70,000 words. Jiang Zhi'ai realizes he's been deceived all along. He has just received a message from his assistant: his boyfriend has just left the Seventh Battlefield and will return to the main city to meet him in three days. His boyfriend is still on the Seventh Battlefield. Then who is the person beside him, wearing his boyfriend's face...? The person hugging him from behind gives a soft laugh, straightens his collar, and covers the kiss marks on his neck. "He won't find out." "Sister-in-law." * Top's perspective: I have someone I like. But he likes my older brother. I drugged him so he could never tell me apart from my brother again. I put on my brother's clothes, wore his pheromones, hugged him, kissed him. I'd do anything for him. I have no limits, because I have only one goal: Before the drug wears off in a month, I want him to get used to my presence, either physically or emotionally. At least one of the two. Theme: