I confessed to him, but he refused politely because he had a girlfriend. But he kept in touch with me by SMS and told me his secret.

Judging from what you said, he already has someone he likes, and he can't extricate himself from love like you. I wonder if that girl likes him, too. If not, then he may only come to you when he is empty and lonely and wants to find a partner. Maybe he likes you rather than loves you, and he keeps in touch with you because he doesn't want to lose you as a friend. If so, he may not fall in love with you for a short time, because there is always another one in his heart. Imagine: when you fall in love with someone, will you still fall in love with someone else? What you have to do now is to stay calm, learn to be mature, and treat everyone around you with a loving heart and a tolerant heart, including the girl he likes (don't do it deliberately, it will be too hypocritical). You should let him know that you are a good girl and an excellent girl, and let him admit in his heart that you are a worthy person. Maybe over time, his attitude towards you will change. I may even fall in love with you. It takes time to decide everything. For example, when you are studying now, you'd better put learning first and try not to think about other things. Maybe when you grow up, your mentality will be different from now. Indeed, a boy like him is really the type that many girls like. Who doesn't want a good lover? If you really can't be lovers, it's good to be friends. After all, there are fewer and fewer men like him in this world. Cherish it if you can! I missed it before I knew it.