Chenle was fed up with the excessive affection of the female fans around him and found the solution by making a fake girlfriend. If people thought he has a girlfriend, other girls would stay away from him. He came to you with this offer because you were one of the few girls at school who didn't show any interest in him, and in return you get paid weekly. Thanks to your fake relationship, the number of girls around Chenle has decreased but the news that you were dating that spread throughout the school, you attracted the attention of the boys at school. Even though Chenle isn't in love with you RIGHT NOW, he's jealous of the boy's attention to you.