Rashi to Genesis 5:32 reads:
אמר רבי יודן מה טעם כל הדורות הולידו למאה שנה וזה לחמש מאות אמר הקב״ה אם רשעים הם יאבדו במים ורע לצדיק זה ואם צדיקים הם אטריח עליו לעשות תיבות הרבה כבש את מעיינו ולא הוליד עד שהיה בן חמש מאות שנה כדי שלא יהא יפת הגדול שבבניו ראוי לעונשין לפני המבול דכתיב כי הנער בן מאה שנה ימות וראוי לעונש לעתיד וכן לפני מתן תורה
Rabbi Yudan said: Why did all the generations [first] have children at [about] a hundred years old but [Noah] at five hundred? [It's because] God had said: if [his children] are wicked, they'll be destroyed in the [flood]waters, which will be bad for this righteous [Noah]; if they're righteous, I'll be bothering him to make many arks. He conquered his wellspring and he didn't father a child until he was five hundred years old so that Japheth, his oldest son, wouldn't be subject to punishments before the flood [arrived]….
From the fact that it's God giving the reason that Noah shouldn't have children (and it doesn't seem like he told Noah the reason), I assume "he conquered his wellspring" means that God — not Noah — stopped Noah from having children.
But everyone else was having children at age one hundred. Do any commentaries, midrashim, or the like describe Noah's response (or perhaps his lack of response) to his lack of children? (Compare Isaac, Rebecca, and Rachel, later in Genesis, whom we see reacting to similar circumstances.)
