Send a text message to my boyfriend to say goodbye, and he quickly replied that he was asleep. Dear friend, what does this mean?

His behavior shows that he is also separated, otherwise he would not be so cold (I understand). He just wants to dump you with his usual indifference, a way of breaking up without hurting each other. You sent him this message and he got what he wanted. (The above guesses are for reference only)

Moreover, the above is not true. He didn't mean to be cruel to you, but in the end, when you said that breaking up embarrassed him, you were just joking and generally didn't care, making him look casual. In fact, he is trying to hide his inner sadness and pretend to be strong (perhaps, some strong men are like this).