How early in the pregnancy did you have your due date given to you by sonography? Did that date ever change as your pregnancy progressed? (I don't mean because of the early birth.) Did the doctor or pediatrician confirm that the baby was born two weeks early?
If the due date of August 2 was accurate, your assumed date of conception would have been November 9. And if your cycles were super regular (which of course you have said they are not), your first day of last period would have been October 26. On the face of it, this all suggests Man 1 could not have been the father.
I assume you are concerned because the baby was born earlier than expected? Did any doctor who examined the baby suggest something different than that you delivered about two weeks earlier than expected? (Such as, did someone say the baby seemed full term?) Unless your sonogram was really inaccurate, it just doesn't sound like the baby was born early enough to suggest Man 1.