I’m an Italian noahide.
In Mishneh Torah-Issurei Biah 12:1, the great Rambam says (English translation by Rabbi Eliyahu Touger):
When a Jew engages in relations with a woman from other nations, [taking her] as his wife or a Jewess engages in relations with a non-Jew as his wife, they are punished by lashes, according to Scriptural Law. As [Deuteronomy 7:3] states: "You shall not intermarry with them. Do not give your daughter to his son, and do not take his daughter for your son." This prohibition applies equally to [individuals from] the seven [Canaanite] nations and all other Gentiles. This was explicitly stated in Ezra3 [Nechemiah 10:31]: "That we will not give our daughters to the gentiles in the land and that we will not take their daughters for our sons."
Rabbi Touger has inserted for this step the following and important note:
Although the verse the Rambam cites as a prooftext refers to the seven Canaanite nations, all other Gentiles are also included as reflected by the verse from Nechemiah. The Tur (Even HaEzer 16) differs with the Rambam, explaining that the verse should be understood within its limited context, referring only to the seven nations. (The Rambam's opinion has a source in the Sheiltot D'Rabbenu Achai Gaon, while that of the Tur is found in the Sefer Mitzvot Gadol) The crux of the difference is the exegesis of the continuation of the verse cited by the Rambam: "For he shall sway your son away." Kiddushin68b quotes Rabbi Shimon as focusing on the motivating rationale for the verse and thus including all those who might sway a person's heart. Thus it refers to all gentiles. The Sages, however, do not accept this perspective.
Here are my questions:
At the outset, is the position of Rambam or that expressed by Ba'al ha-Turim prevalent in the Jewish tradition on this point?
Does the prohibition to all Gentiles include, on the halachic plane, even non-Jews who observe the seven Laws of Noah in accordance with the prescription of Mishneh Torah Melachim uMilchamot 8:11?