I told my ex-boyfriend that if I had a boyfriend, I wouldn't contact or send messages, but he would still send messages. Why do you want to be friends with me?

Then whether he really likes you or has impure motives for you, he will never forget you. Your practice gave him confidence. If you give him his contact information directly, I don't think he will contact you even if he can, because your attitude directly tells him your final decision. So now your attitude makes him feel that he still has hope.