Relations with a gentile woman

What is the biblical and rabbinic prohibition and punishment for a married male Jew (assuming a halchically acceptable marriage) having sexual relations (intercourse) with a gentile woman not his wife? What is the specific prohibition and punishment if the gentile woman is married in the above scenario i.e. a married male Jew having relations with a married gentile woman not his wife. If possible, can you PLEASE list the sources with your answer. Please try and be as specific as possible regarding the actual transgression and whether it is rabbinic or Torah and the punsihment that goes with it. Also, what is the punishment for sexual contact (intimate touching and kissing) other than intercourse, that does not involve the "spilling of seed." Is this a lessor transgression and how does the prohibition and punishment differ from actual intercourse? Thank you. I appreciate your time in helping me with this question.

The prohibition of cohabiting with a gentile woman is the same whether the Jewish man is married or not, and also whether the gentile woman is married or not. The fact that a man is married does not change his status as regards to the variety of forbidden liasons, except for the fact that it is forbidden (by the decree of Rabbeinu Gershom) to marry more than one wife. Other forms of promiscuous behavior are forbidden to married and unmarried men alike. According to the Talmud in tractate Avodah Zarah 36b, The biblical prohibition of cohabiting with a non Jewish applies only within the framework of a marriage (even though such a marriage is not recognized by the halacha) (see Devarim 7;3,4) and the punishment is lashes (the standard punishment for a negative commandment). The prohibition of a one time cohabitation is rabbinic. This position is held by the Rambam (hilchot Biot Asurot ch 12) and the Shulchan Aruch. However, If on cohabits with a non Jew publically, the halacha changes radically and any zealot is allowed to kill the offender. The Rambam writes that one should understand that though this prohibition does not fit into strict rules of punishment, it is crucial for the integrity of the Jewish nation. Intimate touching outside of an illicit marriage would apparently be a rabbinic prohibition, though the Rambam doesn't mention it. Considering the quantity and variety of decrees aimed at limiting social contact with non Jews, for fear of sexual contact, it seems unneccessary to explicitely spell out that intimate physical contact is forbidden.