The trial jury also heard a claim that Nat Fraser was the only person who would gain from Arlene's death.
Giving evidence for the first time since his trial began, Mr Fraser said the couple's relationship was "stormy at times" but he said he still wanted her back when they split up in 1998.
Mr Fraser, of Smith Street, New Elgin, has denied murdering Arlene - along with unknown accomplices - aware that she was seeking a divorce and financial settlement.
At the start of his evidence, defence QC Paul McBride asked Mr Fraser: "Did you kill your wife?"
"No sir," he replied and Mr Fraser also denied arranging for anyone else to kill her or being involved in her disappearance in any way.
When asked about their marriage, Mr Fraser told the High Court in Edinburgh: "It was quite stormy at times."
However, he added that he wanted a reunion with Arlene after they separated in 1998, the year in which Mrs Fraser disappeared.
The court was told that Mrs Fraser had walked out on her fruit and vegetable wholesaler husband before, had stayed in a women's refuge on one occasion and was seeing a solicitor about a divorce.
Mr Fraser said he believed his wife was a good mother to their two children. He paid the bills and gave her a £100 weekly allowance.
However, he said that both he and Mrs Fraser could be "volatile".
Advantage claim
Later advocate depute Alan Turnbull QC, prosecuting, suggested Nat Fraser did not want to hand over any of his money to Arlene, if she was going to leave him for someone else.
"Arlene had no enemies and the only person she had any trouble with in her life was you," he said.
"When you take all of that together it is perfectly clear, isn't it, you are the only person with any advantage to gain from the death of your wife?"
Fraser replied: "I didn't kill my wife. I didn't."
Mr Turnbull continued: "It is clear you were the only person with any advantage to gain from the death of your wife, isn't it?"
"Looks like it, yes," agreed Fraser.
Changes to indictment
Mr Fraser said the couple had fall-outs but would get back together.
He was aware Mrs Fraser had seen a solicitor about a divorce.
Mr Fraser now faces a revised indictment in which he has been accused of murdering Mrs Fraser with unknown accomplices, aware of her divorce plans.
Previous references to "a conspiracy" involving farmer Hector Dick and salesman Glenn Lucas have been removed.
The Crown has alleged that Mrs Fraser may have been strangled at her Elgin home between 28 April and 7 May, 1998.
Mr Fraser has also been accused of an attempted cover-up of the alleged murder.
The trial continues.