As of now, there is no credible or verified news reporting that actor David Eigenberg has publicly broken down in an emotional tribute because a beloved co‑star recently died. Searches of established and reputable news sources show no confirmed report that Eigenberg has made such a statement regarding a co‑star’s passing.

David Eigenberg is best known for playing Christopher Herrmann on Chicago Fire and Steve Brady on Sex and the City and its revival And Just Like That….

There are numerous heartfelt tributes to actors by their colleagues in Hollywood when a co‑star has passed — for example, Friends stars shared a moving statement after Matthew Perry’s death earlier this year.
Likewise, tributes poured in from many in the entertainment community after other actors such as Eric Dane — Grey’s Anatomy castmate — passed away recently.

However, none of the verified news reports currently available link David Eigenberg to a personal tribute in response to a co‑star’s death or a revelation of a “heartbreaking truth” as described in your prompt.

If you’re thinking of a tribute to a specific co‑star, or something said publicly by him about loss, grief, or the passing of someone from one of his shows (Chicago Fire or Sex and the City), please provide the name — I can help look up verified quotes or reactions.