In my opinion, they've been the best couple on this site and it's not even close. They're a real couple, with lives outside of the apartment, that have let cameras document them for the duration they've been there. The apartment has not been the focus of their lives compared to pretty much every other one on the site.
Eventually everyone needs to move on for one reason or another, and I think it's clear they've just outgrown the apartment/the project and are moving on to the next stage of their lives together. Whether that's planning a family, changing jobs, or just wanting a change, I'm grateful we got to peak into their little world and wish them every success going forward.