Is this tosfos saying that there must be an issur d'oraisa (even though there is a g'zeiras hakasuv giving a p'tur from a chiyuv misa) for a Jewish man to live with a married non-Jewish woman? Would this be in addition to the issur of a Jewish man living with any non-Jewish woman (married or single), or would this tosfos consider the general issur to be d'rabbannan? Or is the tosfos referring to the general issur here, and not a special issur of eshes ish? If it is an additional issur d'oraisa, with no additional punishment, how can it be either an issur kollel or an issur mossif?
Sorry, I meant the 2nd tosfos -- p'rat l'eshes acherim.
Marc Diamond, Providence, RI USA
Tosfos brings his proof from the Gemara of Yefas Toar which is Matir an Eshes Ish, so clearly his proof is that there is an Isur Eshes Ish by a non-Jewish woman. Tosfos does not say clearly whether or not he holds that a non-Jewish woman is Asur. However, it is possible to suggest that the marriage is Mosif an Isur to non-Jews.
D. Zupnik