In fact, he hints that she may have been seeing other men during their time together, and that he is just one of many to "walk in", that his may be just one more "pair of jeans" hanging on her door.
While it seems clear that the narrator has put up with his lover's infidelity for a time, he has decided to finally move on, refusing to accept her "silence" about what has happened between them.
He goes on to announce that his lover's "silver tongue has turned to clay, and [her] golden rule to rust," using these metaphors to suggest that she no longer has an enchanting hold over him, and that he is free to leave.
The narrator sees that his "tomorrow's a dream away" only, and this relationship of "today" has in fact "turned to dust," opening his life to new possibilities.
The genre of the song could be considered to be in many categories, ranging from singer-songwriter to country, or from folk to classic rock.