We need strength to let go....

I see playing as an act of releasing air rather than putting out air. One actually needs to build up a certain inner strength to let go. This is especially critical for the upper 2nd to 3rd register, and most indispensable for playing piano in that range.

Try this small but significant difference in mindset the next time you play. Be patient and keep reminding yourself when you notice you're blowing rather than releasing. In the long run, you'll be able to play with much more efficient air management, build up stamina, and be able to have a whole variety in your expressive vocabulary. 

To be able to work with the paradox of tension and release is the key! It's about internalizing, being conscious so that you no longer have to think about it anymore.