The Gemara in Bava Basra 74b famously speaks about both the לויתון (Leviathan) and the בְּהֵמוֹת (Behemoth), both of which were created with a female partner.
In both instances, the Gemara relates that Hashem cut short their lives lest they reproduce and destroy the world due to their immense size and power.
אָמַר רַב יְהוּדָה אָמַר רַב כֹּל מַה שֶּׁבָּרָא הַקָּדוֹשׁ בָּרוּךְ הוּא בְּעוֹלָמוֹ זָכָר וּנְקֵבָה בְּרָאָם אַף לִוְיָתָן נָחָשׁ בָּרִיחַ וְלִוְיָתָן נָחָשׁ עֲקַלָּתוֹן זָכָר וּנְקֵבָה בְּרָאָם וְאִלְמָלֵי נִזְקָקִין זֶה לָזֶה מַחְרִיבִין כָּל הָעוֹלָם כּוּלּוֹ מָה עָשָׂה הַקָּדוֹשׁ בָּרוּךְ הוּא סֵירַס אֶת הַזָּכָר וְהָרַג הַנְּקֵבָה וּמְלָחָהּ לַצַּדִּיקִים לֶעָתִיד לָבֹא שֶׁנֶּאֱמַר וְהָרַג אֶת הַתַּנִּין אֲשֶׁר בַּיָּם
Rav Yehuda says that Rav says: Everything that the Holy One, Blessed be He, created in His world, He created male and female. Even leviathan the slant serpent and leviathan the tortuous serpent He created male and female. And if they would have coupled and produced offspring, they would have destroyed the entire world. What did the Holy One, Blessed be He, do? He castrated the male and killed the female, and salted the female to preserve it for the banquet for the righteous in the future. As it is stated: “And He will slay the serpent that is in the sea” (Isaiah 27:1).
וְאַף בְּהֵמוֹת בְּהַרְרֵי אֶלֶף זָכָר וּנְקֵבָה בְּרָאָם וְאִלְמָלֵי נִזְקָקִין זֶה לָזֶה מַחֲרִיבִין כָּל הָעוֹלָם כּוּלּוֹ מָה עָשָׂה הַקָּדוֹשׁ בָּרוּךְ הוּא סֵירַס הַזָּכָר וְצִינֵּן הַנְּקֵבָה וּשְׁמָרָהּ לַצַּדִּיקִים לֶעָתִיד לָבֹא שֶׁנֶּאֱמַר הִנֵּה נָא כֹחוֹ בְמׇתְנָיו זֶה זָכָר וְאוֹנוֹ בִּשְׁרִירֵי בִטְנוֹ זוֹ נְקֵבָה
And He created even the beasts on the thousand hills (see Psalms 50:10) male and female. And they were so enormous that if they would have coupled and produced offspring, they would have destroyed the entire world. What did the Holy One, Blessed be He, do? He castrated the male and cooled the sexual desire of the female and preserved it for the righteous in the future. As it is stated about the beasts: “Lo now, his strength is in his loins” (Job 40:16); this is referring to the male. The continuation of the verse: “And his force is in the stays of his body”; this is the female, alluding to the idea that they did not use their genitals for the purpose of procreation. (Sefaria translation & notation)
We know Hashem is perfect and does not make mistakes:
הָאֵל֮ תָּמִ֢ים דַּ֫רְכּ֥וֹ אִמְרַֽת־יְהֹוָ֥ה צְרוּפָ֑ה
The way of G-d is perfect; the word of the LORD is pure (Tehillim 18:31)
And as Radak asserts there:
האל תמים דרכו הוא אלי שהיכלת בידו ומה שעושה עושה בתמימות וביושר, ומשלם לאיש כמעשהו והשיב לי כצדקתי ולאיבי כרשעתם
The way of G-d is perfect - He is my G-d who has the power in his hand, and what he does is done in perfection and uprightness/honesty, and He pays to man according to his actions, and He restores me according to my righteousness and to my enemies according to their evil.
I appreciate that the female levyason will be used in the future, and that we recite upon leaving the Succah "שנזכה לישב בסוכה של לויתן" (SA OC 667:1), and likewise with the Behemoth "וּשְׁמָרָהּ לַצַּדִּיקִים לֶעָתִיד לָבֹא" - "He kept it for the righteous in the future", but why make two at the beginning if Hashem knew that He would have to destroy this coupling?