For some people, the only thing that makes them interesting IS their love life, the constant crushes, and dramas, intrigues, and secrets, and phone calls, etc. Once that has settled down, they have nothing else about them that is interesting, which is why they become a boring couple.
Also, consider that though they seem boring to you on the outside, after marriage they have interest mostly in each other, and you don’t see that as an outsider.
As for the routines, they are easy enough to break. The great richness in marriage is that you have someone to share your life with, so compromise is not something bad, it’s something that brings you together. If you don’t want that, then marriage is not for you.
Congrats, Orpheus!