When you've been in a long-term relationship with someone, you're going to argue with them. Just make sure that when you do start an argument, it's for a good reason.
Often, it's so easy to complain and bicker about things that don't matter at all. Which really doesn't make sense, when you think about it. If you're going to have an argument, make it worth something that'll have you grow as a couple.
But to sit around and seriously get angry about inconsequential stuff like this? It doesn't make any sense.