I'm so glad you've decided to go to your guitar lesson. It might be more fun than you think.
I'm not sure if you need to leave a note. I might just ignore him if he knocks (if it's possible) - you sent him a text earlier that said he wouldn't welcome home tonight, so he knows where you are emotionally with his behavior. If his knocking cannot be ignored, I would just tell him go away until he can treat you like you deserve to be treated.
If the car wasn't half yours, I'd send you some shrimp paste from Malaysia called Belechan. This is by far the stinkiest, most vile smelling substance on the face of the planet.
M: 37 H: 36 Married: Aug 13, 2004 Decision to Divorce: July 20, 2008 Reconciled: September 2008 Current: Ambivalence