Robert McNaughton, 51, from Halesowen, set up fake Facebook accounts to troll the woman, West Midlands Police said.
The force said he was "hell bent" on destroying her life after she spurned his reconciliation attempts.
McNaughton, of Tenter Drive, was convicted after a trial of conspiracy to commit criminal damage.
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Sgt Chris Jones said: "McNaughton could not handle being rejected and became hell bent on destroying his ex-partner's life."
During December 2014 and February 2015, he bombarded her with abusive Facebook messages, threatening to release intimate images.
He also hired two men, Matthew Barker and Joden Smith, to carry out a string of attacks on her home, culminating with her car being set on fire in February 2015.
Barker, 44, of Leicester, admitted conspiracy to commit criminal damage and was jailed for 43 months.
Smith, 20, also of Leicester, admitted conspiracy to commit criminal damage and arson, recklessly endangering life and was sentenced to four years at a young offenders institution.
The men were sentenced at Wolverhampton Crown Court on 31 March.

Francesco Schettino was given 16 years in jail last year, after a court found him guilty of manslaughter, causing a maritime accident and abandoning ship.
At the trial in Florence, he is seeking to overturn the conviction, while the prosecution seeks a longer prison term.
The Costa Concordia capsized after it hit rocks close to Giglio island.
On Thursday, lawyers of the 55-year-old captain are expected to argue that the disaster off Tuscany's coast was a collective failure of the ship's crew and others should share the blame for the disaster.
"We will ask that the responsibility of all the protagonists in this affair be redefined, not just that of our client," lawyer Donato Laino told the AFP news agency.
Salvaging the Costa Concordia
Schettino, who has not yet begun his sentence, also denies that he abandoned ship before passengers and crew had been evacuated.
Meanwhile, the prosecution is seeking a 26-year prison term.
If Schettino loses his appeal, he can try again at Italy's highest court - the Court of Cassation.
In February 2015, he was sentenced to 10 years for multiple manslaughter, five years for causing the shipwreck and one year for abandoning his passengers.
Investigators had severely criticised his handling of the disaster, accusing him of bringing the 290m-long vessel too close to shore when it struck the rocks.
More than 4,000 passengers and crew were forced into a chaotic evacuation.
During the trial, Schettino said he had taken the ship so close to land for "commercial reasons" in a bid to please his passengers and those ashore.
He had also rejected rumours that he had wanted to impress his lover, Domnica Cemortan, who was with him at the helm.
Costa Crociere, the company that owned the ship, sidestepped potential criminal charges in 2013 by agreeing to pay a â‚¬1m ($1.1m; Â£779,000) fine.
It is being sued by survivors, the Tuscany region and Giglio island for further damages.
Five other employees, including the helmsman, were handed prison sentences ranging from 18 months to two years and 10 months in plea bargains concluded early in the investigation.
A man who began a hate campaign against his ex-partner, which culminated in her car being petrol bombed, has been jailed for five years.
[NEXT_CONCEPT]
The appeals trial is to begin in Italy of the captain held responsible for the Costa Concordia cruise ship disaster in 2012, in which 32 people were killed.