Who is Howard Dunninger from The Easter Parade: A Novel and what is their importance?

Howard Dunninger is a lawyer that Emily meets while working as an advertising copy writer. Howard is an older man who married a much younger woman only to have that woman choose to walk out on him out of fear of missing out on life. This causes Howard a great deal of heartache and he never truly gets over his wife. In fact, after six years of living with Emily, Howard leaves her to reunite with his ex-wife.