His perspective
Why he may go quiet after the fight
Quiet after a fight can come from overload. That possibility does not make an open-ended disappearance okay.
What his quiet can feel like from your side
You are still wide awake to the fight. The room feels charged, and you want some sign that he understands what happened and is still with you.
Instead, he says very little. Perhaps he leaves the room, looks at his phone, or acts normal later without mentioning it. From your side, the message can feel brutal: he hurt me, then disappeared.
Silence is not a single answer
Conflict can reach the body before clear language arrives: a racing heart, a tight face, words that will not come. If shame or overload is close, speaking immediately may feel impossible rather than connecting.
He may be slowing himself down so that he does not say something worse. He may also be avoiding the conversation, or failing to tell you what the silence means. You cannot know from quiet alone.
The part he still has to do
Space can be reasonable. What makes it bearable is a return: some indication of when the two of you will check in again. Without that, you are left guessing whether the fight is paused, buried, or simply over by his decision.
I will not force this right now. But I need to know when you are coming back, because otherwise I start feeling alone in it.