The Bachelor Sneak Peek: Desiree's Ex Factor

The Bachelor star Sean Lowe receives an unpleasant surprise Monday night on a hometown date with one of his final four women, Desiree Hartsock.

Her ex-boyfriend shows up, asking if they can talk.

An awkward exchange ensues as Des' ex professes his love for her and calls Sean an "actor," while Lowe clenches his fist and sort of threatens the guy.

This has to be scripted ... right?

The Bachelor Clip: Desiree's Ex

Is this something they can get through, or will it seal the deal for Des? Find out by reading The Bachelor spoilers for this week and beyond ... if you dare!

Who should Sean pick?