The pair announced their split in February and it was reported that Simpson, 26, had filed for divorce on the grounds of 'irreconcilable differences'.
There were claims that they might be reuniting after they were spotted at In-N-Out and Taco Bell.
According to TMZ, Simpson has no plans to get back with her estranged hubby, with whom she has a son Bronx.
Wentz, 31, did not want to split with the star but she is reportedly sure that their marriage is over despite wanting to remain civil for their son's sake.