Just some thoughts

How do you know the spark is still there in the relationship? How do you know you still want to be in the relation.
You both are busy in different things, meet each other little, speak about your day not about the other person's day and yet do not feel the vaccuum.
It is not like the heady days of the beginning of the relationship where you messaged each other every hour spoke many times during the day, waited to meet the other. It is not like the earlier times, where the tiff began when the other person did not respond, did not call.
Now you don't even have the time, don't feel the need many of the times.
But a human being always yearns for an intimate relationship But when one gets it, the intimacy goes away. Yes i know it is called a matured relationship. An economist would probably call it the law of dimishing marginal utility. I think you just get used to the other person. I do not like it. I would prefer a relation with some sparks rather than a mature understanding relation where everything is understood with little communication. I think you should strive to keep the spark alive else everything will be routine.