My wife thinks our son died without speaking, but he called me first

Dear Delyara, Our son died by suicide three years ago. My wife believes there were no final calls. That is what I told her. The truth is he called me forty minutes before he died. He was crying. He said he was tired. I tried to calm him, told him to go home, told him we would talk in the morning. I did not understand that he was saying goodbye. Afterward, when my wife asked whether he had contacted anyone, I said no because she was already breaking apart and I could not bear adding that his father had been given a chance and failed to recognize it. I have carried the call alone ever since. Sometimes she says, “At least neither of us had to hear his last moments.” I leave the room. My therapist says the secret is isolating me from the one person who may understand the grief best. I know. But if I tell her now, she will grieve our son again and discover her husband has lied every day for three years.