At this point, I'm pretty sure the two of them are unofficially married. I know that's been the joke since the beginning, but it's getting a little too real to just be a joke anymore
Well in later chapters there are nonchalant kisses and the two of them saying 'I love you the most' pretty casually to each other. Plus they started living together at a flat when they started university. Sharing the bed and such.
Even Sakurako's parents were asking them 'I hope you two don't fight when you're at home' when they went home for a new-year's visit.
The only thing that bothers me is that Sakurako got a haircut later. She is slowly starting to grow her hair back, but she looked so pretty with long hair, I really miss it.