Britney Spears just dumped her boyfriend of 18 months ... after finding out there's a video of him cheating on her that's being shopped around Hollywood.
David Lucado is seen in the video making out with a woman and dancing with her. It looks like they're in someone's living room. The video was shot in early August.
Lucado's reps are saying that David is "very, very in love with Britney. This is unfortunate and he hopes that it all works out." Well, it didn't. After finding out about the incident Britney tweeted:
