In The Glass Menagerie, Tom says he is "more faithful" to Laura than he meant to be. What does he mean by "faithful"?

Tom as
narrator closes the play with aexplaining what his life became after he stormed out of the
apartment in St. Louis, leaving his mother and sister behind. The theme of his speech is that no
matter where he went or what he did, he was never really free of the past:

. . . all at once my sister touches my shoulder. I turn around and
look into her eyes . . . .

Oh, Laura,
Laura, I tried to leave you behind me, but I am more faithful...