Alleged Gilgo Beach Serial Killer's Wife Says Their Kids Cry Themselves to Sleep

The wife and children of alleged Gilgo Beach serial killer Rex Heuermann are reeling in the wake of his arrest ... with all the crippling anxiety and sleeping difficulties you'd expect for a family suddenly thrust into a nightmare.

The suspected killer's wife, Asa Ellerup, says the couple's son and daughter are crying themselves to sleep.

Heuermann's wife revealed the toll the grisly allegations are taking on her family in an interview with the NY Post, telling the publication she often wakes up shivering from anxiety in the middle of the night.

As we reported ... Heuermann's family recently returned to the Long Island home where cops believe he gruesomely murdered his victims.

The couple's 33-year-old son, Christopher, got super emotional as he sat down on the front porch last week.

Now, Asa says the home is a complete mess as a result of a 12-day search by police ... and the couple's daughter, Victoria, feels like the family is being treated like animals.

Living and sleeping in that home under the gruesome circumstances seems like an impossibly traumatic situation -- but Heuermann's wife says they have nowhere else to go.

Among the alleged damage left by police ... cat litter boxes strewn about, a couch in shambles, a broken guitar, and some damaged collectibles.

Heuermann has been charged with 3 murders ... and investigators are digging into a theory he might have killed the victims in the home while his wife and kids were out of town.