The relevant episode for Scarus is 4.8. Antony has just achieved an unexpected victory against Caesar. He and Scarus come on stage from the scene of battle; both have fought courageously. Scarus refers to the wounds he received in the engagement, but is laughing them off. The one that looked like a 'T' has received an added slash, making it into an 'H'.
Enobarbus certainly feels he has betrayed Antony. We see his decision to leave at the end of 3.13. Yet his decision, founded apparently on pragmatic reason, leads to his death: ironically, of a broken heart.
We get an alternative perspective on Enobarbus' defection from Antony himself. He says that his (Antony's) 'fortunes have/Corrupted honest men', and sends Enobarbus his portion of treasure.