Whitbread has refused to sign a new contract at the Den as he looks to move to a bigger club, but after a move to Peterborough broke down last week over his wage demands, Jackett admits there has been no more interest.
"We're disappointed that (he wants to leave) but that's his view. We have to get on with it," Jackett told Sky Sports News.
"Peterborough made an offer and got some way down the road towards accepting that and agreeing it but it has broken down on his personal terms.
"I believe now that the interest is dead and we have had no other bids for him during the course of the summer."
Whitbread himself is keen on a move to a Championship club in an attempt to boost his chances of earning a place in the United States' World Cup Squad.
He added: "I need to step up to that level and try and prove myself there, especially with the World Cup next year for the States. That level I think is a lot more recognised."