Jake Broke It Off
We're told Jake believed Vienna was "stepping out" with Gregory Michael -- an actor on the ABC Family show "Greek."
The story had been out that the 2 were flirting at a recent event, but apparently Jake took it to heart.
Sources at "The Bachelor" say they don't know if Vienna was in fact doing the nasty with Greg -- but Jake was convinced enough to end the relationship in the last 24 to 48 hours.
UPDATE: Vienna just tweeted, "The accusations of me cheating are completely fabricated. 100% False." Our 'Bachelor' people say whether she cheated or not, Jake thought she did.