I would try another store, because once your handle gets too dark, that's really hard to clean up. Don't wear the bag anymore without a twilly, and a lighter one than the bag I would say.
I think I know where you say the leather is separating, is it the sides at the top? It looks worn there. I would be concerned about that.
Here's my advice- I know you paid a LOT for this bag, but no bag, even an Hermes, is meant to be carried every day for a couple years without showing some wear and tear. Other brands would have looked like they would go in the donate pile if you carried them so much, so this is a testament to H's quality.
I remember Chanel service once told me to never carry a bag for more than a month at a time, which I never do, max 2 weeks, if you want to keep it in good condition. Use your bag, but give it a break for a few days every month, and take it to another store for a spa, because everyone's tolerance for wear on their bags is different. Good luck and let us know what Brussels says.