@Ayanna Ah. Here it has the connotation of "Honeymoon is over, so now they get lazy and revert to bad habits that annoy each other." So yeah, the hard work of marriage, in the sense that not everything is perfect and romantic anymore like it was on the honeymoon, and you're just going to have to deal with your partner's flaws.
We've extended the metaphor to a lot of things, though. Like you can have a honeymoon period for a new job, a new roommate, lots of different situations. It was that [auch fig.] that made me think I could do the same in German.
