So the honeymoon's over and the two of you fight a lot,huh? And from what I gathered from your post,it seems to me that it's YOUR fault.
You're the man in this relationship,therefore,it's your responsibilty to lead.
You've been here long enough to know not to listen to what women say.
That thing she said about you saying "please" and "thank you",as if you're 5 years old,don't listen to that. And arguing about things that don't really matter,like the name of a song is just plain juvenile. Let's say that the two of you start to argue over the name of a song,and you're the one who's right.
Does it really matter? By arguing with her,(even if you're right),all you do is make her feel bad. That's ALL you accomplish. You argue her down until she admits you're right,then you get your little ego boost from being right,while she walks off feeling like dirt,and all this over the name of a song?
It's not like you on Jepardy and you risked all your money by making it a "true daily double",and you HAVE to get the answer right. Or like the two of you are trying to diffuse a bomb,and you're arguing over which wire to pull,the red one or the blue one. Unless it's something that's really,really important,don't waste your time and energy arguing over things that don't matter one way or the other,because you might win the arguement,but bit by bit,you're losing your girl.
I believe that the real reason she's arguing and starting fights is because the chemistry she felt when you first started dating has died off a little. She's acting and behaving exactly like you would be doing if there was no sex in the relationship. You would be angry,rude,and unhappy in the relationship as well. In other words,her emotional needs aren't getting met,and yes,it's your fault.
The good news is that this is easy to fix. It's simple. Think back to when you first approached her. To what you said,what you did,the way you talked to her,the way you looked at her,etc. Just go back to treating her like you did in the beginning,do it on your own,without having a talk with her about what's going on. But when you do it, do it a little bit at a time,not all at once,otherwise she'll think you're crazy. If you treat her like you did in the beginning,I guarantee you that she start responding to you like she did in the beginning. Her feeling will change,and even she won't know why.
I know I was a bit hard on you,but I tell it like I see it.
Good luck man.