Sarah-Jane Cunningham, 38, was left devastated by the affair and confided in her friend Teresa Church in a phone call the evening before she died at home on July 23 last year.
Ms Church said in a statement read to the hearing: ‘She knew he was having an affair.’
Norfolk area coroner Yvonne Blake recorded a conclusion that Mrs Cunningham’s death was due to drug and alcohol abuse – but could not conclude that Mrs Cunningham, of Old Catton near Norwich, had intended to kill herself.
Mrs Cunningham, who suffered from ‘severe anxiety’ was admitted to hospital following overdoses in October 2015 and 2016.
A mental health worker said Mrs Cunningham’s death was a ‘cry for help’ following three bereavements, including her father in 2008.
Her sister, Kim Dodd, 37, said Mrs Cunnigham had ‘destructive’ relationships with her husband Stuart and alcohol.
She said: ‘She was addicted to her husband. They brought out the worst in each other but she would not leave him because she could not cope without him.’
Mrs Dodd said that Mr Cunningham changed after a motorcycle accident in 2014 which left him with post traumatic stress disorder.
She said: ‘It became quite apparent alcohol was a big feature of both her and her husband’s life at the time.
‘The overdose was an attempt to communicate to her husband her frustrations rather than an attempt to die.’
After the inquest, Mrs Dodd said: ‘The outcome today was never going to bring my beautiful sister back, but I was pleased to find out that out of the terrible situation some good has come in the fact that the procedures and policies of the mental health team are being changed to ensure that other people like my sister do not slip through the net.