But I worry for CC. He has self-esteem problems already, and I can't help feeling it's my fault he is having to deal with this now.
That is HIS choice to be with you, HIS feelings to own. Let him own his emotional baggage. Everyone holds their own bag.
If you want a graceful response? Apart from mere "ok" like "Ok, I hear ya. My ears are operational?"
"Thank you for your concern. In this matter you do not need to concern yourself for my sake."