Woman are from Venus and Men are from Mars. Read it, despite it's awful wording, and examples, there is some interesting and useful facts within it.
I was in a 5 year relationship, lived with her for 4, it went sour last year, we have sort of tried again recently, but it wasn't going to work, so i told her i didn't want any more contact. I still think about her numerous times a day and miss her, but i don't think it is meant to be. Sure we argued, and i put in an enormous amount of effort, and tried to talk about things.
It sounds like you're in a rut mate, don't let it continue. Read the above mentioned book, and talk to her, and listen. Each day when you get home ask her how her day was. Don't take the male high ground and tell her solutions to her problems, just listen and be comforting. Acknowledge her when she is talking and don't have the TV / Radio on. The flowers occasionally will work, but full court ones are carp! Get her some sent to the house from a florist, she will know you have gone to some trouble and thought then.
Good luck fella, don't give up, it isn't always greener on the other side.