The Gemara in Kiddushin 21b writes:

בביאה ראשונה דכ"ע לא פליגי דשרי דלא דברה תורה אלא כנגד יצר הרע

With regard to the first act of sexual intercourse (between the soldier priest and the gentile woman), everyone agrees that it is permitted, as the Torah spoke only in response to the evil inclination.

Rashi over there underlines this fact that it is permitted only as a means to deal with the Yetzer Hara.

The implication is that in the thick of war Hashem recognises the urges that soldiers may have, and therefore rather than forbid such an act, it is permitted with the caveat that he has to deal with the circumstances, namely, to take care of her and not completely disregard her after being with her.

This is further clarified by the Rambam in Mishneh Torah, Melachim UMilchamos 8:2 where it writes:

וְכֵן בּוֹעֵל אִשָּׁה בְּגֵיוּתָהּ אִם תְּקָפוֹ יִצְרוֹ. אֲבָל לֹא יִבְעָלֶנָּה וְיֵלֵךְ לוֹ. אֶלָּא מַכְנִיסָהּ לְתוֹךְ בֵּיתוֹ. שֶׁנֶּאֱמַר (דברים כא, יא) "וְרָאִיתָ בַּשִּׁבְיָה אֵשֶׁת יְפַת תֹּאַר". וְאָסוּר לִבְעל אוֹתָהּ בִּיאָה שְׁנִיָּה עַד שֶׁיִּשָּׂאֶנָּה

Similarly, a soldier may engage in sexual relations with a woman while she is still a gentile if his natural inclination overcomes him. However, he may not engage in sexual relations with her and then, go on his way. Rather, he must bring her into his home as Deuteronomy 21:11 states 'If you see a beautiful woman among the prisoners...You shall bring her into the midst of your home...' It is forbidden for him to engage in sexual relations with her a second time until he marries her. (Touger Translation)

So whilst we give those engaged in the battlefield the means to satisfy their urges, it is clear that the yefas toar is not be treated like a proverbial piece of meat, as the man must duly take responsibility for his actions.

The notion of Yefas Toar is something that is very hard to comprehend. However when taken within the context of war and the resulting environment, Rabbi Frand helps to paint a clearer picture. He writes here:

War is an environment the likes of which we should never know. It is a dehumanizing experience, which does crazy things to people. One has only to read the paper and listen to the news about abuses that have taken place in recent times, in and around situations of war and conflict. War has a pernicious and corrosive effect, even on people who are spiritually elevated. That is how such a thing can happen, as “you will see her in captivity and lust for her”.

The Gemara in Kiddushin 21b writes:

בביאה ראשונה דכ"ע לא פליגי דשרי דלא דברה תורה אלא כנגד יצר הרע

With regard to the first act of sexual intercourse (between the soldier priest and the gentile woman), everyone agrees that it is permitted, as the Torah spoke only in response to the evil inclination.

Rashi over there underlines this fact that it is permitted only as a means to deal with the Yetzer Hara.

The implication is that in the thick of war, Hashem recognises the urges that soldiers may have, and therefore rather than forbid such an act, it is permitted with the caveat that he has to deal with the circumstances, namely, to take care of her and not completely disregard her after being with her.

This is further clarified by the Rambam in Mishneh Torah, Melachim UMilchamos 8:2 where it writes:

וְכֵן בּוֹעֵל אִשָּׁה בְּגֵיוּתָהּ אִם תְּקָפוֹ יִצְרוֹ. אֲבָל לֹא יִבְעָלֶנָּה וְיֵלֵךְ לוֹ. אֶלָּא מַכְנִיסָהּ לְתוֹךְ בֵּיתוֹ. שֶׁנֶּאֱמַר (דברים כא, יא) "וְרָאִיתָ בַּשִּׁבְיָה אֵשֶׁת יְפַת תֹּאַר". וְאָסוּר לִבְעל אוֹתָהּ בִּיאָה שְׁנִיָּה עַד שֶׁיִּשָּׂאֶנָּה

Similarly, a soldier may engage in sexual relations with a woman while she is still a gentile if his natural inclination overcomes him. However, he may not engage in sexual relations with her and then, go on his way. Rather, he must bring her into his home as Deuteronomy 21:11 states 'If you see a beautiful woman among the prisoners...You shall bring her into the midst of your home...' It is forbidden for him to engage in sexual relations with her a second time until he marries her. (Touger Translation)

So whilst we give those engaged in the battlefield the means to satisfy their urges, it is clear that the yefas toar is not to be treated like a proverbial piece of meat, as the man must duly take responsibility for his actions.