The eye in the sky don't lie ... so says Iggy Azalea who claims Nick Young cheated on her in THEIR HOUSE ... and she caught the whole thing on video.
Iggy went on social media -- claiming she has no idea if Nick's other is pregnant or not -- per various media reports -- but says her NBA ex-fiancee was definitely messin' around.
"I have never even been told by nick that his baby mother is pregnant," Iggy wrote before dropping the hammer.
"I broke up with Nick because I found out he had brought other women into our home while I was away and caught them on the security footage.