Hotton, the court heard, was feeling "disconnected" at the time and could not afford ADHD medication he needed.
Days later, he spoke with another former partner via Instagram.
Tempers flared when the woman's new boyfriend intervened and told Hotton all contact had to go through him.
The defendant told the man he would kill anyone who got in his way.
The ex-partner, in a statement before the court, said she feared for her and her children's safety.
She believed Hotton was using class A drugs and said she did not know what he was capable of.
The defendant also pleaded guilty to a charge under the Harmful Digital Communications Act, relating to abusive comments he made to the first ex-girlfriend on August 23.
Judge Dominic Flatley noted Hotton had similar convictions from 2018, saying, "This seems to be part of how you operate."
Counsel Alan de Jager acknowledged the impact of the threats but stressed his client had no intention to follow through on them.
Hotton was sentenced to four months' community detention, 12 months' intensive supervision and 150 hours' community work.