Simpson's ex-husband, recording artist and TV personality Nick Lachey married his longtime girlfriend Vanessa Minnillo in July.
"Everything is up in the air," an insider told UsMagazine.com about the Simpson-Johnson wedding. "She can't figure out what kind of day she wants. Some days she wants a big wedding in Hawaii, then other days she wants something closer to home."
"She was so gung-ho about planning their wedding, and now she's gone dark," added a second friend. "She won't commit to a date."