In the world of feelings, where your mood swings don't matter to him, the cold war after a quarrel, he can go on with his life without care, leaving you alone to face emotional distress.
Your giving, whether material or emotional, seems to turn a blind eye and enjoy your care with peace of mind, but does not leave you a place in his heart.
The way he chooses to communicate is silence, and when something happens, he chooses to escape, making your waiting the norm, and making you choose to break up through cold violence.
He begins to be secretive about you, no longer as open and honest as he used to, unwilling to let you know about his life, bored with your inquiries, as if you were invading his privacy.
He always uses "overtime" as an excuse to tell you that he is busy and has no time. However, you learn from his mutual friends that he just chose to hang out.
He no longer has an exclusive nickname for you, no more sweet words, and your intimacy fades away. When you express your longing, he will choose to change the subject and avoid discussion.
He is no longer willing to share the bits and pieces of his life with you, and your contact is becoming less and less, as if you are in a question-and-answer relationship every day, and the freshness of each other is not as good as before. On every memorable day, he will selectively forget, use all kinds of excuses to prevaricate you, turn a blind eye to your expectations, and continue to forget next time.