Jefferson County Deputy Jonathan Allen told 7NEWS he forgives his wife despite allegations she tried to poison him by spiking his dinner salad with potentially deadly foxglove plant leaves in 2008. As the deputy left his Highlands Ranch home to work as a police-dog handler Wednesday afternoon, he said he will attend his wife Lisa's May 14 sentencing on felony assault involving drugging a victim in Douglas County District Court. She faces three to six years in prison, according to a plea agreement detailed in court records. Asked why he forgives his wife, the 38-year-old Allen replied: "'Cause I'm supposed to and holding back hate doesn't help anything." Just weeks after her arrest, Lisa Allen filed for divorce. The couple has a young daughter, and the divorce case resolution has been postponed until after the wife's sentencing, court records state. "It's been tough. It's been rough," the husband said. "It's definitely created empathy in my heart for other victims," the deputy added. "And it's affected how thorough I am when I do my job. And I want to make sure I do it to the best of my ability." It's also given him new appreciation for the old saying: "Love your neighbor as yourself. Don't do that kind of thing, you know," he said. Allegations that Lisa Leigh Allen, 42, attempted to poison her husband surfaced in the summer of 2008. Jonathan Allen told investigators it was unusual when his wife called him while he was at work on the evening of June 5, 2008 to say she'd made him spaghetti and salad for dinner. The deputy said he usually just ate whatever his wife had made for herself and the couple's daughter, who was 3 years old at the time. It was a special meal for the couple, who had argued the night before, Lisa Allen later told a detective, according to a Douglas County sheriff investigator's statement supporting her arrest. As the family began dinner, Jonathan Allen said he found it odd when their toddler grabbed an olive from one of her parent's plates and "Lisa took the olive from (the child), wouldn't let her eat it, and put her to bed," the arrest affidavit said. "This was also unusual, because it is customary for (the toddler) to eat from both of their dinner plates," the affidavit stated. It's unclear if the child took the food from her dad's plate, because that part of the document was redacted by court officials. Jonathan Allen noticed his wife, who normally served iceberg lettuce, had made a salad of romaine lettuce mixed with "unusual" leaves with serrated edges, the affidavit said. The husband said the leaves "tasted bitter to him (and) he didn't finish the salad," the affidavit said. Jonathan Allen checked the refrigerator for bags of the unusual leaves and didn't find any. But as the deputy went out onto the backyard deck that night to check his "canine partner," he noticed two potted plants on the barbecue with the label "foxglove," the affidavit said. The plant with ornamental bell-shaped flowers had leaves with the telltale serrated edges -- just like the ones in his salad, an investigator wrote in the arrest affidavit. That night Jonathan Allen said he checked the couple's home computer's Internet browser history and found someone had been looking up information about foxglove and how "the foxglove plant is toxic to humans, and can cause heart problems," the affidavit said. The deputy said he suspected his wife had done the research, the affidavit said. Someone had visited a Wikipedia webpage explaining that foxglove produces the heart medication digitalis and its toxic chemicals can be "deadly," the affidavit stated. The drug can make an individual's heart beat slow down -- or race, the investigator wrote. "The entire plant is toxic (including the roots and seeds), although the leaves of the upper stem are particularly potent, with just a nibble being enough to potentially cause death," the Wikipedia site warns. "Thus, the digitalis has earned several more sinister names: Dead Mans Bells, and Witches Gloves," the website states. About an hour after dinner, Jonathan Allen said he began having heart palpitations and stomach cramps and was wheezing, the affidavit said. The next day, the husband met with a Douglas County sheriff's investigator. He wept and was apprehensive as he explained that he suspected his wife had tried to poison him, the affidavit said. He also gave the investigator one of the serrated leaves he'd saved from his salad, photographs showing the foxglove plants and the computer's Internet browsing history. The deputy went to a Littleton hospital where tests showed he had digitalis, a chemical from the foxglove, in his system, the affidavit said. Investigators arrested Lisa Allen that day. She told a detective that she and her husband had been having marital problems for several years, the affidavit said. Lisa Allen said she was taking Prozac for depression. The husband said the couple had been trying to have another baby and his wife had a miscarriage the previous fall, the affidavit said. Lisa Allen said she and her husband had argued the night before the spaghetti dinner and "he was still angry with her" when he left for work the next morning, the affidavit said. "While Jonathan was at work, she researched poisonous plants on the Internet," the wife told the detective, according to the affidavit. "She wanted to buy her sister a plant, and wanted to make sure she didn't buy a poisonous plant." Lisa Allen said she'd bought a plant at a nursery on Federal Boulevard before coming home to make the spaghetti and salad dinner that night, the affidavit. But when the detective showed her photographs of the two foxglove plants on the couple's deck, the wife said she had never seen them before, the affidavit stated. Yet an assistant manager at Wilmore Nursery on County Line Road in Littleton told 7NEWS Wednesday that she provided investigators with a receipt showing Lisa Allen bought the foxglove plants there. "She was very interested in how big the (foxglove) leaves were and how big the roots were," Leah Crews recounted at the nursery. At the request of investigators, Crews examined garbage seized from the Allen home and identified parts of foxglove plants amid the trash. "In her trash, she had a lot of different plants in there. I'm assuming she had been gardening for some time," Crews said. "You know I'm glad, I could help them ID the plant, and everything. Normally, I don't get cases like that," the nursery manager said. Crews said she has helped in cases where pets have accidentally ingested poisonous plants. "But I've never had a case where it was maybe intentional," she said. Lisa Allen was initially charged with premeditated first-degree attempted murder, domestic violence and two counts of assault with a deadly weapon, according to court records. Her defense attorney, Scott Robinson, said his client was facing 48 years in prison. Yet, 21 months into the investigation, the wife pleaded guilty to the felony assault for drugging a victim, and the district attorney dismissed the more serious charges, according to court records. Robinson said although Lisa Allen pleaded guilty, she did not admit to poisoning her husband.