Who is Bob Langley from Valis and what is their importance?

Bob Langley is Gloria Knudson's ex-husband, with whom Horselover Fat has socialized in Oakland, CA. Bob is a self-confessed schizoid who phones Fat with news of Gloria's suicide. At the graveside, Bob unemotionally places a rose on the coffin while Fat, overwhelmed by emotion, flees to his car. When Fat asks Gloria's mother for a photograph of Gloria, Bob becomes irrationally angry.