Harry Sarkar has been banned from ever becoming a police officer again.
A misconduct hearing was told the officer's lies about her supposed illness, death and funeral got him bereavement leave and flexible working hours.
He would have been sacked had he not resigned as his actions amounted to a "significant abuse of trust", West Midlands Police said.
The student officer resigned in March.
He did not attend the gross misconduct hearing before Chief Constable Sir David Thompson on Thursday.
West Midlands Police held a misconduct hearing – but Mr Sarkar did not attend
PA
Chief Constable Sir David Thompson condemned Mr Sarkar
Nick Potts
The claims about his fake girlfriend were made between October 2020 and June 2021.
A force professional standards team said Mr Sarkar's bosses signed off "sick leave" and additional benefits, taking his lies at face value.
Mr Sarkar received three days' bereavement leave and benefited from more flexible working hours in comparison to those enjoyed by his colleagues.
With a number of officers testing positive for Covid during the second and third national lockdowns, the impact of his claims came at a particularly difficult time.
In a statement, Sir David said: "This case concerns a protracted period, with the officer creating a fictional relationship where the other party was suffering from cancer and died.
"This enabled supervisors to allow enhanced flexibility in his working.
"These 'truths' were repeated and developed over a sustained period of time."
Concluding the hearing, Sir David added: "No other sanction would have been suitable and the officer would have been dismissed without notice and accordingly."