'Why didn't you tell anyone?'

'Nobody asked.'

Sodapop always felt like the middle man in his brother's arguments, always felt like his struggles weren't as important, like he was just supposed to be this happy, go lucky guy 24/7. So he never told anyone otherwise. He didn't cry in front of others, didn't complain, didn't argue (not much at least).

It hurt but, hey! He's supposed to be the happy brother. Ponyboy is the smart one, and Darry's is the strong one.

Why change it now?

Darry is already stressed almost all the time, he and Ponyboy fight a lot so, Sodapop needs to be the happy, "carefree" one to keep the peace.