The original meaning of “porneia” was actually prostitution. It came to have a broader meaning of general sexual immorality including fornication, incest, rape, and cohabitation. An unlawful marriage is obviously form of sexual immorality. Be that as it may, I will go with the translation of “fornication.” Again, with this translation everything that I pointed out in post 26 is still true. By addressing only the technicalities of the translation you are avoiding the fact even the translation you prefer supports the Catholic understanding of what our Lord taught.
Mat 19:9 And I say unto you, Whosoever shall put away his wife, except it be for fornication, and shall marry another, committeth adultery: and whoso marrieth her which is put away doth commit adultery.
Ya right...