When he gives out the final rose on The Bachelor's March 1 finale, Jake Pavelka must choose between two women. But one of those women, Vienna Girardi, has a second guy on her mind: Lee Smith, her ex-boyfriend from back home in Florida.

"She wants to get back together with him," a source says in the new issue of Us Weekly. Indeed, multiple Girardi insiders confirm to Us that Girardi, 23, remains head over heels for Smith -- to perhaps unhealthy extremes.

When The Bachelor on the Wings of Love wrapped production in November, Girardi rushed home to reunite with Smith at his Florida apartment. To her surprise, Smith had already taken up with a new woman, local waitress Cassie Heaberlin. "[Vienna] got so angry that she walked right into the house and went to the bedroom," one source reveals.

She even physically threatened Smith and Heaberlin, another insider claims. The couple "woke up to see Vienna standing at the foot of the bed holding a wine bottle, like she was going to hit them with it."

If she was so in love, why would Girardi participate on The Bachelor? "She was just on to be famous," a source explains. "She never thought she'd make it so far."

It was Smith, in fact, who hooked his then-girlfriend up with a Bachelor casting director. And when Girardi left to film the show, "Vienna told Lee she'd be back for him."

To find out more about Vienna's shocking past (including naughty new pics), whether Tenley is too boring for Jake, Ali's Bachelorette gig and insight from Jillian Harris and Ed Swiderski, pick up the new issue of Us Weekly -- on newsstands today!