The Celtics employee with whom Ime Udoka had an affair helped make all his travel arrangements ... and that job sometimes included organizing travel for his fiancee, Nia Long.
Sources connected to the couple and the NBA franchise tell TMZ ... one of the staffer's duties included planning Udoka's team-related travel, and we're told she was also involved in booking travel for Nia to come to Boston or to road games.
Perhaps most upsetting for Nia is that the employee had a hand in Nia's arrangements to move to Boston permanently, according to our sources.
TMZ broke the story ... Nia had just moved east a little over 2 weeks ago with Kez, her 10-year-old son with Ime.
The Celtics are not releasing the name of the employee, but we're told Nia has been told who she is.
Team President Brad Stevens got choked up Friday during a news conference ... saying the scandal had been particularly upsetting for all their female employees -- due to speculation about who had the affair with Udoka.
As we've reported, the team suspended its head coach for the entire 2022-23 season after what it says was a months-long investigation into his conduct.
We've reached out to the Celtics for comment, but no word back yet. Ditto for Nia's reps.