I dont get why we need sparks why do we need it?

I lost the sparks, and im still with my boyfriend but I still love him. If you love the person dont you need to stay with them? I mean the sparks/excitement will go away any time and were comfortable use to that person. And people say if you loose the sparks then you cant have a relationship. But I mean your use to the person, and the excitement will be gone any time and if you love them stay with them. I think that spark feeling is just a infatuation. I choose to love my boyfriend. Im use to my boyfriend and im happy and I dont see why I have to leave him just because Im not excited anymore. So I dont get it why do we need the sparks even if their gonna go away and we have to waste our time trying to ignite the stupid sparks??