Why am I feeling emotion? (Saikixreader)

Chapter 8

Your POV
After I sung, Saiki kept staring at me. "...Is there something on my face?" I asked, slightly getting red. Saiki shook his head. "No, you are just...really something else." He smiled. My face went red, and he grabbed my hands. "You really are
cu—." The door opened, and a girl walked in. "Coffee jelly?" Me and Saiki both nodded, and the girl went over to Saiki. She gave him the jelly, touching his hand longer than she had to. She looked at him and mouthed "Your cute." I felt rage and jealousy storm through my body. "What do you think you're doing?" Saiki asked her, and shook her off of him. "I'm obviously here on a date with my girlfriend. So unless you want me to get physical, leave me alone." He said, pulling me close to him. "O-Oh yeah? Well prove that she's your girlfriend." The girl said, getting angry. He looked at me. "Okay." He said, leaning in and kissing me. The kiss was sweet, and I could feel his emotions for me in the kiss. He was passionate, I could tell he really loved me. He got on top of me on the couch, and continued to kiss me, the kiss was getting more intense-all of the bottled feelings spilling into the kiss. The girl ran out and I pulled away, thinking he finished proving his point. "Oh no you don't." He pulled my face towards his again, and continued to kiss me until we both needed air. We panted  and our faces were red, and I looked down. "So, your my boyfriend, huh?" I said, smiling. Saiki looked at me and grabbed my hand. "If you'd like me to be." He said, and I knew his introverted shell had come off. He opened up to me, made himself vulnerable to pain. "Of course I do." I giggled.