The reality couple became engaged on the 14th instalment of the romance reality franchise, but announced their separation earlier this week.
In a statement to Entertainment Weekly, creator and executive producer Fleiss said: "It is painful. We've been on a roll lately with a bunch of happy couples in succession.
"Mr and Mrs. Jason Mesnick, Ed [Swiderski] and Jillian [Harris], Ali [Fedotowsky] and ???… Strong relationships are even emerging from Bachelor Pad. This break-up caught me totally by surprise. I really feel bad for Jake and Vienna. (sic)"
Pavelka has said that he is "deeply saddened" by the split, while Girardi has dismissed speculation that she was unfaithful and recently tweeted an anonymous quote which said: "Relationships are like glass. Sometimes it is better to leave them broken than try to hurt yourself putting it back together."