Richard Gayer’s ex agreed he could stay at the property 'until he got himself sorted' after they split in November, but she told him to leave on January 25, said prosecutor Annelli Pritchard.
He grabbed hold of her hand, snatched her £1,000 phone and snapped it into a number of pieces.
Rebecca Meadows, mitigating, said Gayer, who has no previous convictions, moved in three years previously and 'had no reason to think anything would change'.
She said: “He had been the breadwinner throughout the relationship and made improvements to her home.
“They were completely and utterly a unit so it came as a complete and utter surprise to him when she started a relationship with someone else.
“Shortly afterwards he was made redundant.
"In an ideal world he would have moved away somewhere else.
"But he didn't have anyone else he could go and stay with.”
On the day in question she became annoyed and followed him upstairs, saying she wanted him to leave immediately, and he grabbed her hand.
Ms Meadows said: “It wasn't a strike or a blow.
“It was just a moment of frustration.
"He accepts she doesn't want anything more to do with him and is okay with that.
"He found a new home the following week.”
Gayer, aged 61, of Laurel Crescent, Nuthall, admitted criminal damage and assault, when he appeared at Nottingham Magistrates Court, on April 23.
He was fined £120 with £85 costs, a £48 surcharge, and £1,000 compensation.