Good afternoon nickberard,
Welcome to the Apple Support Communities!
I understand you and your wife are using the same Apple ID account for iCloud and are using iPhoto with macOS 10.12 on your separate computers. You'd like to see the photos from each of your cameras on each Mac. The best way to accomplish this would be to:
- Use a different Apple ID for iCloud data for either you or your wife. Each of you has to have your own, unique Apple ID for this to work.
Create, manage, and use an Apple ID
- Set up Family Sharing, so that you can share purchases and have a shared family album.
Family Sharing
"Family Sharing makes it easy for up to six family members to share App Store, music, movie, TV, and book purchases, an Apple Music Family Subscription, an Apple Arcade subscription, an Apple News+ subscription, an Apple TV+ subscription, and an iCloud storage plan — all without sharing each other's Apple accounts."
One adult in your household—the family organizer—chooses a feature for your family to share and invites family members to join. After the family members join, Family Sharing is set up on everyone’s devices automatically. Then if you want to add more services to share with your family, the organizer can update your Family Sharing settings at any time.
When you set up your family, a shared album is created automatically in the Photos app on all family members’ devices. Everyone can add photos, videos, and comments to the album whenever they like and get notified when something new is added."
Set up Family Sharing
"Family Sharing requires a personal Apple ID signed in to iCloud. If your family has purchase sharing turned on, music, movies, TV shows, and books can be downloaded on up to 10 devices per account, five of which can be computers. iOS 8 or OS X Yosemite or later are required to set up or join a Family Sharing group."
Once this has been done, I would suggest updating your Macs to macOS Catalina (10.15.2) or macOS Mojave as the iPhoto application has been replaced by Photos. Make sure you have a Time Machine backup of your respective computers before proceeding with this.
Back up your Mac with Time Machine
How to upgrade to macOS Catalina
Switch to Photos from iPhoto on Mac - macOS User Guide - macOS Catalina
Take care.