I'm guessing that you two are young. The spark is an elusive sensation that you can't realistically sustain over the course of a long-term relationship. It's the giddy sensation of two people on their best behavior having fun together, and you lose that when you get to know each other well. You can waste the rest of your life on short-term relationships, endlessly chasing the spark, or you can start appreciating what can follow the spark, the warm glow of a solid, happy relationship together. Understand that the warm glow doesn't come easy, you will need to maintain good quality communication, along with trust, respect and teamwork.
Good decisions come from experience. Experience comes from bad decisions.