Nick Young is fiercely trying to save his relationship with Iggy Azalea ... with multiple sources telling us it's hanging by a thread.
We're told by people very close to the couple that both Iggy and Nick are pissed about the D'Angelo Russell video ... in which Nick apparently admits to cheating on Iggy over the summer.
Our sources say the engagement is in jeopardy -- and Nick and Iggy are "not on good terms."
Sources close to Nick tell us he's crushed -- telling people he's madly in love with Iggy and is focusing on trying to repair their relationship.