How does Michael's pride inhibit his search for Susan and Elizabeth-Jane?

Michael was embarrassed, he couldn't bring himself to tell people what he'd done.

The truth was that a certain shyness of revealing his conduct prevented Michael Henchard from following up the investigation with the loud hue-and-cry such a pursuit demanded to render it effectual; and it was probably for this reason that he obtained no clue, though everything was done by him that did not involve an explanation of the circumstances under which he had lost her.