It was the most highly-publicized case of “marriage fraud” in recent memory: a Canadian woman abandoned by her Guinean husband only a month after he arrived in this country, the revelation that he had previously fathered a child in Africa, and his subsequent deportation for not declaring the existence of a dependent. But paternity tests may now show that the so-called fraudster was in fact not the child’s father — and that the alleged cad may have been exiled from his new life without good reason.