WHy do we fight so much?

WE have been together for 7 years, and we have still been staying strong in some way. but we fight almost every day.... we do love each other but why do we half to fight???? he is always accusing me of things, and i dont see how and why he would think that. if i wanted some one else i would have left him along time ago. and i have been told him that i would never step out on us. Yeah we go through hard times but who dosent,, you know. i just want to be with him and not argue every dam day about the same shit. Ever since the day i meet kc my world became me and him. I dont even know how to be with another person cause im so used to him. I feel like myself and ....i just want to be happy with him, im not asking for much.