At an earlier sentencing hearing Christopher Morrow's defence barrister told the judge that at the time of the offences his relationship was going through "emotional difficulties" and he "was not having a sexual life while his fiancée was pregnant".
He added that Morrow, who also pleaded guilty to possessing an extreme pornographic image, was "extremely remorseful".
Morrow, who sat with his eyes downcast throughout the hearing, had at first denied all the charges, but eventually admitted the blackmail.
The judge said Morrow had "no consideration for the consequences" of what he had done and had prioritised "his own needs and wellbeing over others".
The PSNI began to investigate in 2023 after several women made reports regarding a man named Joseph they had met on Tinder.
The profile picture that Morrow used to catfish the victims was actually the image of a man based in Cambridge.
Judge Kerr said the offending went "beyond mere sexual gratification".