SSIS-309 Fucking cousin for 3 days and 3 nights without a break

Rika and I have been dating since high school. Perhaps because we've been in love for so long, the feelings between us are no longer the same as before. Recently, Rika has gotten to know a final year man who exceeds me in every way, making Rika feel uncertain. That man is preparing to travel and has invited Rika to go along; she agreed and took this opportunity to reassess our current relationship status. Although Rika hasn't said anything, I can still sense that something is happening. One day, while sitting alone in the park near my house, Konan passed by. She knows everything and sat down to listen to my thoughts, chatting with me and helping to improve my mood. On the day Rika was going to travel, Konan waited for me outside and offered to replace Rika as my girlfriend for three days! And during those three days, I felt like I was back in the early days of love. I got to know her better and gradually developed feelings for her. I tried to confess my feelings, but she refused, saying that I was Rika's boyfriend, her sister, and that there would never be a result between us...