In many instances, we know the ages of personalities in Tanach and when they got married. In some cases, we aren't given enough information within the text and in some of those instances, the Midrashim or later works provide the missing ages. Often, this can be very enlightening for understanding the interactions between characters in Tanach.
For example, there are various Midrashic and later sources which discuss the ages of Avraham and Sarah being either 25 and 15, or 50 and 40.
As another example, We know that Yitzchak was 40 at the time he married Rivka, and that she was either 14 (according to Tosafot on Yevamot 61b) or 3 (Rashi to Gen. 25:20).
What is the largest known age difference between a married couple in Tanach?