He likes his privacy and doesn't feel the need to broadcast his life on social media.

But.....you are a person enmeshed in social media, so you feel the necessity to broadcast your life on the internet.

Its merely a difference in states of mind.

So you see it as him being ashamed of you, but to him, he may just be private. Not so long ago, people didn't have a need to tell everyone and anyone of their relationship status. Not so long ago, people were happy just to have someone, and only told those in their close circle, ie only people they actually interacted with face to face.

You might want to examine your own reasons for broadcasting your relationship status, most likely to people you don't know all that well anymore. (Most people have hundreds+++ of friends but only see a very small percentage of them in person.)

ETA

You honestly think this is passive aggressive behavior? It doesn't even come close!!!