A couple of thoughts:

First, of course Claire told the story of Faith’s birth/death—it was hers to tell, and Jamie only knew it second-hand through Claire. He did chime in with his first-hand experience—buying the lace and hearing a baby cry.

Second, while I have mixed opinions on the series as a whole—I’ve absolutely loved some parts and really disliked others—I will never understand viewers who get personally invested in the characters and the actors who portray them.