Boy trouble. Please help!!!!

So I've been texting this boy for months and we both really like each other (well I thought) and he's so so good looking and he's one of the nicest boys in my class but... I went back to school last week and I heard one of the other girls say that he started texting her about a month ago. He is still texting me the same way he always does and I know he's not the type of boy to play around with girls. He doesn't know that I know about the other girl and I don't know what to do:( Should I keep texting him or should I tell him I know about the other girl. My friends want me to block him but I still really like him even after this. Someone please tell me what I should do🙏🏻