Perhaps the biggest lie anyone has ever told you about commas is that they represent breaths.
“Add a comma anywhere you pause to breathe,” is bad advice I see a lot from online “writing experts” and others. I saw it again yesterday, which is what triggered this post.
Commas don’t indicate a pause to breathe. Commas can’t just indicate a pause to breathe, because that would mean that a person with greater lung capacity would use far fewer commas, if any, whereas a person with small lungs or a condition such as asthma would appear to be using the Shatner comma.
If you insist on linking commas to anything the reader does physically, link them to voice inflection (real or imagined).