I was in the same boat for a while, and the impression I got was that it didn't really matter how many times I came over so long as; I wasn't planning on staying or working, and that anything I could do to prove that was good to them. I wouldn't expect this every time you visit though, after all, while you have a habit of visiting the US regularly you also have a habit of leaving.

On another note, it never ceases to amaze me the number of people who have transatlantic relationships.