@aFFi
That's the point of the story. The story revolve around the couple and how they truly become a proper married couple.
This slow phase was to be expected since it's a slice of life genre, romcom are second.
There's no goal in this strory, but we could easily assume how the story ends. My guess is they fully done all the things that married couples do, ex; had a child.
This is why we interested reading this manga, we want to know how the couple progress with their married life.
If I may said it honestly, the art style and plot actually pretty mediocre, but somehow people are interested reading it.
So far, I'm more interested about the background story of the wife, she seems to be hiding something. I don't know what it's but if I may guess that she is ill, and won't live long. This is why she came out of nowhere and rush the marriage.
But hey it just my personal guess.