What do you think about Damon's letters to both, Bonnie and Alaric?
Hi! Sorry for the late answer.
I think Damon was brutally honest with Ric about how he felt. He was miserable and he wanted to be sincere with his best friend, no excuses, no trying to make him believe his choice was for the greater good. His choice was for himself and his unhappiness and misery.
In the letter he wrote to Bonnie he expressed his fears. He was honest about not wanting to endure a pain and probably failing despite Bonnie’s best efforts to help him be a better man like Elena was able to.