builder hugged his fiancee and told her “I love you” moments before stabbing himself to death at their home.
Heartbroken Sally Grigson watched in horror and begged her partner of 13 years to stop, but he told her he “couldn't take any more”.
Simon Thompson, 44, had proposed to Miss Grigson just a week earlier.
Miss Grigson told an inquest at Worthing Town Hall that Mr Thompson had seemed absolutely fine apart from a couple of instances of 'odd behaviour' in the run up to his death.
The couple celebrated their engagement with a holiday to Devon on May 29 but Mr Thompson insisted they go home a day early showing signs of paranoia.
The 44-year-old self employed builder and decorator had suffered a nervous breakdown in 1995 but his brother Jeremy said he had made a full recovery.
When Miss Grigson and Mr Thompson returned from Devon to their flat in Latimer Road, Worthing, on June 4 she did not give him his post.
The next day he opened his letters and told his fiancee he had a bill from the Inland Revenue for £3,000.
She said that although he seemed concerned he said: “I've paid some of it and have put £500 aside.”
She said because he had recently bought a motorbike and the 'phone didn't stop ringing' with new customers she did not feel he was overly worried.
She said: “I asked him if he wanted lunch and he said no.
“As I walked away he stood up and put his arms around me. He said 'Sally I love you so much'. We cuddled and kissed and I said 'I love you too'.”
Moments later she heard a noise and saw Mr Thompson standing in the doorway of their bathroom.
She said: “The blood was across his chest and from his waist down.
“He had a knife in his right hand and said 'Sally I can't take anymore'.
“His face didn't look like him, his eyes were strange and his face was screwed up.
“I said 'Oh my God, what have you done. I screamed 'give me the knife'."
She added: “I was so scared, I started to panic and shouted 'please don't leave me'.”
Mr Thompson barricaded himself in the bathroom and Miss Grigson called 999. Paramedics broke the door down at about 2pm.
He was taken to Worthing Hospital where he was pronounced dead from a stab wound to his heart.
Pathologist Iain Morrison said although Mr Thompson had received multiple self inflicted injuries it was likely that one stab wound had killed him.
Deputy coroner for West Sussex Martin Millward thanked Miss Grigson for giving what he described as a 'harrowing account' of her ordeal.
He recorded the verdict that Mr Thompson had committed suicide while the balance of his mind was disturbed.