David Armstrong walked free from court last week after being acquitted of murdering his lover's husband. The jury decided he had acted in self-defence.

Reporter Sam Thomson spoke to the woman whose fling had fatal consequences - and found a family torn apart by anger and grief.

When Barbara Banks left her husband for another man she knew things would not be easy - but she never expected it would end in death.

The 44-year-old is racked with guilt over her brief affair and its dreadful consequences.

Every day she recalls the early hours of December 15 last year when her husband Tony, in a frenzy fuelled by a mixture of anger, drink and prescription drugs, confronted her lover.

The father of her two children, he tried desperately to force his way into the ground-floor flat where she and lover David Armstrong were living.

She remembers the sound of the dustbin lid crashing through the kitchen window and Tony trying to crawl through the jagged hole.

He was shouting "You're a dead man" at Mr Armstrong and had a fishing knife in his back pocket.

He had broken into the property before, once smashing the flat up with a hammer and assaulting his wife.

Barbara recalls the sight of the 12in knife descending upon her husband.

The 43-year-old suffered five wounds from the blade wielded by Mr Armstrong and collapsed in a pool of blood.

He died in hospital an hour later.

Mr Armstrong, a 39-year-old builder of Mill Road, Lewes, was found not guilty of murder and manslaughter after a jury at Lewes Crown Court accepted he was in fear of his life and had acted in self-defence.

Barbara, of Cowfold Road, Brighton, said: "I did something stupid and thought I might get the chance to make it right but now I never will.

"Even when I was with Armstrong, I always had the feeling I might get back together with Tony but now he's gone for ever."

The couple's marriage had been strong for most of its 24 years but, with their two children grown up and no longer at home, their relationship grew gradually weaker.

The situation took a turn for the worse when Mr Armstrong entered their lives in spring last year.

He had met Mr Banks in London a few months earlier and they became friends.

Soon afterwards Mr Armstrong moved to Brighton.

Barbara said: "At first I thought he was a bad influence on Tony because they both started to get drunk together a lot.

"Then Armstrong would start coming over almost every night.

"Tony would fall asleep and we would stay up playing cards and talking.

"He can be quite charming and he came along at a very vulnerable time for me."

Flirtation eventually turned into a fling and Barbara left Tony in October.

She moved into her daughter Natalie's house before secretly moving in with Mr Armstrong.

Barbara said: "To be honest I still don't understand why I did it.

"I suppose I wanted to completely opt out of the life that I had.

"But it wasn't fun. All we would do is sit around drinking."

A month later Tony found out about the relationship and confronted his wife.

He lost his temper and smashed up Mr Armstrong's flat with a hammer.

Four weeks later he returned to the flat at 3.30am after bombarding Barbara and Mr Armstrong with phone calls.

Barbara said: "I was worried but I never thought he would come over.

"I pleaded with him to go to Natalie's and sober up so we could talk about it in the morning.

"When he did turn up, Armstrong tried to ring the police but I asked him not to.

"I knew Tony would get arrested because he was out on bail for what he did before.

"I wish he had been arrested now.

"At least he would still be alive."

The next few minutes will remain in Barbara's mind for life.

She said: "I remember trying to push Tony away from the window but I couldn't.

"Then I remember seeing the knife come down again and again.

"It was said in court I was screaming hysterically all through it but it was only when I saw the knife I started yelling.

"Afterwards I rang the ambulance. I couldn't bear to go outside because I was frightened of what Tony would look like lying on the ground.

"I was terrified of what I would see.

"Now I wish I had gone outside to hold him one last time."

In her original statement, which was read out in court, Barbara told the police: "David did it to save the two of us from Tony" and "Something had to happen to stop him getting into the flat.

"It was him or us."

Confronted with the statement in court, she told the jury: "Yes, but there are other ways."

Barbara has remained close to Tony's family following his death.

She said: "I have had no contact with Armstrong whatsoever since that night.

"I never want to see him again.

"I felt sick every time I looked at him in court.

"Afterwards I stayed with Natalie and my granddaughter Olivia. Tony's brother John stayed with us for three months and helped us come to terms with what happened.

"I would not have been able to cope without the family sticking together."

Barbara is angry with the jury's verdict and feels it has badly affected her attempts to cope with her husband's death.

She said: "I just feel desperately, desperately sad.

"When couples split up they can either get on with their lives separately or try to patch things up.

"We can never do that now.

"Tony was a lovely, lovely man."