The second was attacking Scott and Kylee Guy's near-new home with a splitting axe and writing obscenities in 2009.
But he denies he killed Scott Guy, who was shot dead on his driveway in the dark on the morning of July 8, 2010, and is defending the charge at trial in the High Court at Wellington.
In reply to his wife's questions, Macdonald said: "I didn't hate them. It was a bit of fun, really, and just to annoy them."
Crown prosecutor Ben Vanderkolk asked her if she noticed any change in his behaviour after the arson but she hadn't seen anything that made her think he was involved, even when they visited the scene with their children.
But she did see a change in him later.
"I would have thought a change after the damage to the property which was a few months after - that's when I started to notice the change, [but] otherwise, no."
On the night Macdonald and an accomplice burned the house down - the trial has heard they ignited it using diesel - she didn't hear any sirens.
She also could not be sure what her husband's movements were that night, or if he left the house.
Macdonald eventually told police the truth about what happened, during a four-hour interview with two detectives. He was charged with Mr Guy's murder later that day.
In that interview, he told them he was not "extreme" enough to take someone's life and was not a "psycho".
Earlier at the trial yesterday, a detective told of visiting Aorangi Rd in rural Feilding following the arson attack to look for clues.
Felicity Mansell said she went to the Macdonalds' home and spoke to Mrs Macdonald, who she initially didn't realise was Scott Guy's sister.
While Ms Mansell was speaking to her, Macdonald came into the dining room but Ms Mansell didn't speak to him.
The jury also heard yesterday how the Guy family were told not to speak to anyone about the disappearance of three chocolate Labrador puppies because that information could be helpful to police when questioning suspects.
The Crown alleges Macdonald killed the three puppies about the time of the murder to try to create a false lead. They say distinctive footprints found next to Mr Guy's body were also found near where the puppies were kept.
Nikki Guy, Scott's sister, recalled how "animated" Macdonald had been when he returned from feeding the puppies the day after the murder. He said he told police that three of them were missing.
Stunned family members wondered if there was a link between the puppies and Scott's death. Nikki Guy said: "I remember, 'Well who would have taken the puppies? Was it a clue in the murder? Did someone take them on purpose?' We were theorising."
Macdonald told them they weren't allowed to tell Kylee Guy about the missing puppies because it would upset her too much, she said.
Mrs Guy, in her third appearance in the witness box, said "Scotty" gave her a "beautiful" Labrador called Katie just before they got engaged.
Katie had eight puppies, one of which was given to a close friend while the rest were to be sold. She fought back tears when she read out a flyer they made advertising the puppies.
Mrs Guy took one of the flyers into Hunting and Fishing, the Palmerston North store owned by Macdonald's father, on July 7, 2010 - "the day before it happened", she said, referring to the day her husband was killed.
The trial continues.
