where did the romance go..

me and my fiance have been together for 3 years(best friends since high school). in the beginning I was everything he wanted it was me 24/7 when he'd be with friends he still message me yeah not asap but still a text flowers not just on holidays little love letters cute things. now 3 years later I feel like there's no love, arguments more than before,not even noticing I'm here. the only thing I can think about is "they try hard to get you and once they have you they stop trying." what am I supposed to do to keep us together or should I just realize that this "spark" is over.