An unread message is easy to keep checking when you care about the person who sent it. Silence leaves a gap, and worry is quick to fill it.
Separate facts from predictions
The fact may be that a reply has not arrived. “They are angry” or “I ruined everything” are possible interpretations, not confirmed facts. Naming that difference can loosen the loop.
Set a boundary with checking
Repeatedly opening an app rarely gives new information. You could choose a time to check again, then put your phone somewhere else and return to a task or person in front of you.
Talk about communication expectations
People have different habits and schedules. When it feels appropriate, discuss what kind of communication works for each of you. Aim for clarity and flexibility rather than a rule that one person must always be available.