Darrell Rudyj, 26, told the woman: "If I ever get the chance, I promise I will kill you myself," on April 1, said prosecutor Abigail Hill.
Other emails read:
‘When I slap you in the face at least you will know the reason’;
‘Just know this is going to end in violence’;
‘I'm not going to lie, I'm going to batter you’;
‘You're going to die. Your own partner won't be able to look at you. Be careful, you might just get acid in your face.’
Nottingham Crown Court heard their 'turbulent' four-year relationship came to an end in 2018, and Rudyj was angered because he had missed a family event on March 29. In 2015 he was convicted of battery and criminal damage against the same woman.
She later told police she was 'anxious and frightened and no longer felt safe in her home,' said Mrs Hill.
She temporarily moved to another address, but later retracted her statement and withdrew her support for the prosecution.
Rudyj, who has seven previous convictions for 18 offences, was last in court in 2018, for possession of cocaine and cannabis, when he received a two-month tagged curfew.
Julia King, mitigating, said: "An 18-month community order would provide him with the support he needs to address the issues that caused him to offend."
She said he has spent the last two months in custody and his family have paid his rent, but if he was locked up he would lose his flat.
"He really has used the time to make a plan to lead a better and more productive life," Ms King said.
Rudyj, of Lathkill Close, admitted causing a person to fear that violence would be used against them, on April 5.
On Thursday, Judge Stuart Rafferty QC told him he was a 'hypocrite' and described the messages as a 'diatribe of hatred.'
He sentenced him to 12 months, suspended for two years, with a two-year community order that includes a 31-day programme and ten rehabilitation days.
"If you come back before me, bring a bag," the judge told him. "Because you will be going downstairs."