Trying to understand a sudden breakup + possible Canada move + confusing timeline — did I miss something?

I recently went through a breakup after a long-term relationship and I’m struggling to understand the timing of everything.

During the relationship, we spoke about moving abroad together. We had just moved in together in London and things seemed normal on the surface.

Around 3 months before the breakup, my ex met a girl from Canada through work. When she came to the UK office to visit, they were hanging out a lot over the course of a week. My gut found this strange as he’s not overly social, and they are on completely different teams and live in different countries. I questioned him at the time, saying it felt a bit strange not to meet her, especially as he had met all my friends. He dismissed it and said it was nothing.

Fast-forward a couple of months, he suddenly broke up with me in the most brutal way. There had been no indication or discussion beforehand that anything was wrong — in fact, he told me he loved me the week before, and he was physical with me the day before.

On the day of the breakup, he did it in a very cold way, went quiet, couldn’t really explain himself, and made attacking comments that didn’t make much sense at the time. I left the flat in shock and when I came back a bit later, all his bags were packed. He then left without another conversation.

I was completely blindsided and confused, so I messaged him afterwards trying to understand what had happened. Eventually, he said that he still cared about me and was attracted to me, but no longer loved me. He also described himself as a “cynical, bitter, unhappy, angry at the world” person, and said I had brought out the good in him, but that he internalises everything and doesn’t really show that side in relationships. He said this is “just who he is” and that he’s had depression most of his life but hasn’t really sought help for it.

The relationship is over, but I’ve struggled a lot with how it ended. If someone falls out of love, I can accept that over time, but I found the way it ended really painful — I thought at the very least we were friends and that he would treat me with more care. I’ve always been there for him emotionally through his depression, but he never fully opened up to me.

Months later, I found out (through LinkedIn) that he had changed his location to Canada and was trying to get jobs there. I messaged him again (I know I shouldn’t have) and he confirmed he is planning to go to Canada.

This has left me really confused because these were things we had spoken about doing together in the future.

He says nothing was going on with this Canadian girl, but I’m not sure what to believe.

I feel quite stuck and angry because I trusted him and we were building a life together. Now I feel like I’m left in a very lonely city trying to rebuild my life while he is getting what feels like a fresh start by moving to Canada.

Would really appreciate any perspective from people who’ve been through something similar — especially around sudden breakups and partners seeming fine right up until they end things.