I really can't thank you guys enough. These replies have been extremely helpful. We've been racking our brains over this for a while but now it's clear how to proceed. We'll include only our permanent residences in our home countries as the places we've lived, say we have not lived together yet, and then include passport stamps, photos, boarding passes, etc. as evidence of having spent time together traveling.
I'm going to upload separate pdf files for our passports, including every page of each one (I have one that expired recently but has most of my stamps for our travels together). But in addition to this, should I combine all the various types of evidence for each trip together into one file, including photos of us in a single country alongside the boarding passes to and from that country, and also the passport stamps from both out passports for entering and exiting that country? Or upload one pdf file with all the travel photos from all the different countries, another with all the boarding passes, and let them connect the dots themselves so to speak? I have a lot of passport stamps from solo trips before we met so it might be a slog for them to search through it all.