There is a phrase saying "Out of sight out of mind."
There is "The idea that something is easily forgotten or dismissed as unimportant if it is not in our direct view."
But I think the Bible teaches us the opposite.
I think the Bible teaches us that when beloved brothers/sisters in Christ are not in our direct view,

we are more eager to see them with intense longing as Paul did.
That's why I think the Bible teaches us 'Out of sight, fullness of heart'.