Gabi has moved on. That much is easy to see. When she writes on her blog, she mentions friends that do not include me. She doesn't check in on this blog anymore. All the times we talk online, it's always me that initiates the conversation - and when I do, it takes her an absolute age to reply. During today's meeting she whips her phone out every minute, checking if other friends have tried messaging her in the time spent with me.
I think it hits you in the gut, realising that your ex can be happy without you. I think you see your relationship as the peak of their happiness - after all, in your mind who can possibly make her happier than you are right now? Once that relationship dies, and she goes on about her life, it's a kick in the balls to think that she might look back negatively on your time together, and decide that you were wrong: because it's now (single) that she's happiest.
Of course, I liked being her special somebody, but this isn't about ego. I think it's more about that feeling you get in your chest when you're in love; your brain and heart confirming their feelings. When your ex makes it clear you're not special to them anymore, it does break your heart - because you know those feelings won't ever be repeated. It has died, and gone away.
Today with Gabi, I can see she's not who she once was.
In her mind, neither am I.