John added: "When we did, it really meant so much to so many people.
"I'm just grateful that my wife was courageous enough to do it … One of the ways we could carry on Jack's memory was taking pictures of that moment. I was worried, like, I don't want to commemorate this pain … [but the photos are] something to remember him by."
And John - who has four-year-old daughter Luna and Miles, two, with Chrissy - thinks the "challenges" the couple have been through together only make them stronger.
Speaking to Good Morning America in a joint interview with Chrissy, John shared: "We've been through so many challenges together and they've made her stronger, and I know that doesn't always happen when people go through tragedy."
"But I feel like the challenges we face together have made us feel even more sure about who we are together as a couple, and who we are as a family."
• For support for bereaved parents visit sands.org.nz
• 0800 543 354 (0800 LIFELINE) or free text 4357 (HELP) (available 24/7)
• https://www.lifeline.org.nz/services/suicide-crisis-helpline
• YOUTHLINE: 0800 376 633
• NEED TO TALK? Free call or text 1737 (available 24/7)
• KIDSLINE: 0800 543 754 (available 24/7)
• WHATSUP: 0800 942 8787 (1pm to 11pm)
• DEPRESSION HELPLINE: 0800 111 757 or TEXT 4202
• NATIONAL ANXIETY 24 HR HELPLINE: 0800 269 4389