A question of commas

[DAgent]

Add some more grain while I, as a non-native English speaker, notices the following:

"To my wonderful partner Sara,
Without her I could never have done this."

It is a dedication, about (and basically addressed to) Sara. So, IMHO, the 2nd line should be (if we maintain that capital) "Without whom I could never have done this."

or, replace the comma after Sara with a semi-colon:

"To my wonderful partner Sara;
Without you I could never have done this."

Either way, a comma after 'Without you' seems unnecessary to me. That 2nd line is a clear, short statement that should run unhindered by comma's.

I think I like your second example best of all here. It makes me feel like the writer is looking at her partner while making a little speech at a ceremony and looking right at her to thank her.

And I do think it should be "Whom" as well, it's kinda odd that the grammar checkers never brought that up either!