What is the ruling on one who swore by Allah and His verses and His books that he would not travel again, and then traveled, and what are the consequences of this oath?

You owe one expiation for an oath, due to the repetition of the oath concerning a single matter, and because swearing by the attributes of Allah does not necessitate more than one expiation. Your oath falls under the category of a "lajaj" vow, whose ruling is a choice between fulfilling it or offering an expiation for an oath. Since what was vowed is forbidden (adultery with the mother), it is not permissible to fulfill it, and thus only an expiation for an oath remains due upon you. You must also offer sincere repentance for uttering such a reprehensible statement.