The Hebrew of Ezra 10:3 reads:
וְעַתָּ֣ה נִֽכְרָת־בְּרִ֣ית לֵ֠אלֹהֵינוּ לְהוֹצִ֙יא כָל־נָשִׁ֜ים וְהַנּוֹלָ֤ד מֵהֶם֙ בַּעֲצַ֣ת אֲדֹנָ֔י וְהַחֲרֵדִ֖ים בְּמִצְוַ֣ת אֱלֹהֵ֑ינוּ וְכַתּוֹרָ֖ה יֵעָשֶֽׂה
The Hebrew term, highlighted in red, means “my [sovereign] Lord,” referring to Yahweh. However, from the context, it is not Yahweh who is being addressed here; as one commentator correctly noted:
My lord. The Hebrew has “the lord” (adonay) referring to God. This is impossible in the context, however. It must refer to Ezra. With a minor change of vowels (adoni) we can arrive at “my lord.” This shows that Shecaniah held Ezra in high esteem. Ezra came as a Persian official but also as a priest and someone with a special knowledge of the law. From Ezra 7 on he is depicted as an able man, for which he received due respect. While standing before the supplicating Ezra who was dumbfounded with grief Shecaniah encouraged Ezra. Shecaniah as a man of action wanted Ezra to execute his proposal, namely, to send away the foreign wives. They had to act immediately to exterminate the grave sin from their midst. They had to renew the covenant with God in great haste. The sense of urgency comes out clearly in the imperatives of v. 4. (F. Charles Fensham, The Books of Ezra and Nehemiah [The New International Commentary on the Old Testament; Grand Rapids, Mich.: Eerdmans, 1982], 135)
I highlight this as it shows that (1) the Masoretes were not perfect in their vocalization of אדני and (2) that competent scholars, including those who are conservative Evangelical Protestants, disagree with the likes of James White et al., who claim that there is no difference in אֲדֹנָ֔י (Adonai) and אדֹנִ֗י (adoni), an issue that comes up in terms of the theology of Psa 110:1 (109:1, LXX)—some, such as White, claim that the psalmist has Yahweh speaking to Adonai (also Yahweh), and that God in the Old Testament, while numerically one, is multi-personal(!) Such is the nonsense one has to engage in with the biblical texts to uphold a man-made dogma!