Nathan Collings, 34, of Abertillery, appeared at Swansea Crown Court on Tuesday 7 November.
He previously pled guilty to several offences, including stalking and three counts of controlling and coercive behaviour and two charges of threatening to disclose private sexual photographs or films, at an earlier hearing.
He was dismissed at an accelerated gross misconduct hearing on Monday 23 October.
Deputy Chief Constable Rachel Williams said:
“The offences committed by Nathan Collings are both appalling and shocking.
“We fully recognise the significant impact that these types of crimes have on victims.
“I would urge anyone who believes they are a victim of these crimes to come forward safe in the knowledge that they will be taken seriously and treated with compassion and respect.
“This case shows that survivors of this type of abuse will be believed when they take that first step to speak out as justice has been served with Collings now facing the consequences of his actions.
“This behaviour undermines confidence in police officers, most of whom are working tirelessly to make their communities safer and free from crime.
“The public rightly expects police officers to act within the law and display the highest standards of behaviour, so it is reassuring to know that this individual will never be allowed to return to policing following his dismissal from our service.”
Collings was jailed for two years and six months.
He did not appear in person at the misconduct hearing last month, but after the allegations of gross misconduct were found proven he will be placed on the College of Policing’s barred list.