The former One Direction star died after suffering a fatal fall in Buenos Aires on Oct. 16.
The singer helmed the mic for the legendary hard rock band from 1978-1981 before being replaced by longtime vocalist Bruce Dickinson.
"This cruel world is always [too] quick to judge someone," she added.
On top of federal criminal charges, the embattled rapper and mogul has now been sued more than two dozen times over alleged sexual abuse.
The couple broke up in 2013, but Peazer said the late 1D member had recently reached out to her before his death last week at 31.
They lavished Detroit with praise after Donald Trump recently disparaged it.
“I'm sorry I couldn't save you. Love you, oh how my heart misses you," she wrote.
"Please give Liam the little dignity he has left in the wake of his death," the singer wrote.
"Nothing about the past few days have felt real," added the influencer in her tribute to the star.
The singer who died at 31 on Wednesday after a fall from his Buenos Aires hotel room also told his younger self that he'd one day meet the "most amazing person," his son Bear.
