Both versions of the passage in question are correct, each in its own way. The NET's notes (footnote/text note number 5) are instructive regarding the apparent naivete of God in the passage under consideration:
Or “I said to her, ‘Come back to me!’” The verb אָמַר (’amar) usually means “to say,” but here it means “to think,” of an assumption that turns out to be wrong (so HALOT 66.4 s.v. אמר 14 [Koehler, L., W. Baumgartner, and J. J. Stamm. The Hebrew and Aramaic Lexicon of the Old Testament. Translated and edited under the supervision of M. E. J. Richardson. 5 vols. Leiden: Brill, 1994-2000]); cf. Gen 44:28; Jer 3:19; Pss 82:6; 139:11; Job 29:18; Ruth 4:4; Lam 3:18.
Furthermore, the NET continues in this vein in a study note:
Open theists suggest that passages such as this indicate God has limited foreknowledge; however, more traditional theologians view this passage as an extended metaphor in which God presents himself as a deserted husband, hoping against hope that his adulterous wife might return to him. The point of the metaphor is not to make an assertion about God’s foreknowledge, but to develop the theme of God’s heartbreak due to Israel’s unrepentance.
In perhaps too many passages to enumerate, the writers of Scripture use anthropomorphisms to describe God and his dealings with the human race, generally, and his chosen people in particular. There is the very real danger in hermeneutics not to take into account these anthropomorphisms (in essence, projections of human characteristics onto God).
God is not man, and man is not God. True enough, we creatures are created in God's image. Nevertheless, we will never attain to the sui generis nature of our Creator. Isaiah is instructive in this regard:
"For my thoughts are not your
Nor are your ways My ways,"
declares the LORD.
"For as the heavens are higher
than the earth,
So are My ways higher than
And my thoughts than your
thoughts" (55:8-9 NASB Updated Version).
Therefore, when we approach passages such as Jeremiah 3:6-8, we do well to remind ourselves of the limitations of language in describing God's dealings with humankind. Even the human characteristics and failings of our species, such as jealousy, for example, are but poor and inadequate--albeit instructive-- descriptions of our infinitely holy God and of the relationship he desires to have with his image-bearers.
Is God a jealous God? Of course. Exodus 20:5 and Deuteronomy 5:9 make this eminently clear. The questions we need to ask ourselves, however, are "In what way is God jealous?" and "How is God's jealousy different from human jealousy, which can often be petty, and may even be a completely inappropriate and sinful emotion in some cases?"
The typically jealous husband, for example, who flies into a jealous rage when he sees his wife talking with another man, may be guilty of adultery himself, and his jealousy and the anger associated with it may simply be his way of projecting his guilt onto his wife, even though her conversation with another man may be totally innocent.
Therefore, when we come to passages such as Jeremiah 3:6-8, we need to tease out the elements of the analogy or metaphor which are true of God and reject those elements which are not true of God. We are guided in this process by considering not only the immediate context of the passage under consideration, but also the context provided by ever-widening circles such as the complete writings of a given author (in this case, the writings of Jeremiah the prophet), all the other prophetic books which may include the same or similar metaphor/analogy, and ultimately the entirety of Scripture, since the Scriptures cannot be broken (see John 10:35 in context).
There is no doubt, for example, that the Scriptures say a great deal about the covenant of marriage. Moreover, what is true about the nature of that covenant says a great deal about what is true of God. For example, within the human covenant of marriage, there is an exclusivity of relationship such that the husband and wife pledge their absolute fealty one to the other. Any breach of that exclusivity is a violation of that pledge, and the consequences of that violation are always a sin against God as well as against the husband or wife.
In Jeremiah, the implied metaphor is that of a disillusioned husband who simply cannot understand how his wife could prove to be unfaithful. In his heart-sickness, he longs for the good old days in which her fealty was unquestioned and her loyalty absolute. Surely, he thinks, she will return to me once she recognizes her folly and realizes how hurtful her behavior is to me.
How, then, and in what ways are the elements of this metaphor true of God? Well, given the truth about God that he is a jealous God, his first and most basic commandment to his image-bearing creatures is:
"You shall have no other gods before me" (Exodus 19:3).
This commandment does not mean that the LORD our God (YHWH) is to be the first and foremost God in our lives, and all other gods are merely to fall into line behind Him. God forbid! The one true God is to be the only God in our lives, the one with whom and around whom we build our lives together. We are to be one with God, just as the "two . . . become one flesh" in the marriage covenant.
Earlier in Jeremiah (again, the second circle of context, the first circle being the original, later text), we read,
" … Thus says the LORD, 'I remember concerning you the devotion of your youth, the love of your betrothals, your following after Me in the wilderness, Through a land not sown '(Jeremiah 2:2)." [“…כֹּה אָמַר יְהוָה זָכַרְתִּי לָךְ חֶסֶד נְעוּרַיִךְ אַהֲבַת כְּלוּלֹתָיִךְ–לֶכְתֵּךְ אַחֲרַי בַּמִּדְבָּר, בְּאֶרֶץ לֹא זְרוּעָה.”]
It's as though the LORD in this passage is longing for the "good old days," the days of "first love" (cf. Revelation 2:4), when Israel was, for a time, devoted to the LORD her God as they made their way from the land of slavery to the land of promise by following after the LORD in obedience to his statutes and commands.
One commonality of the two passages is of course the marriage metaphor or analogy, but a second commonality is the emotional valence which inheres both passages. In chapter 2, God longs for the former fealty of his wife Israel--albeit that that fealty was tested on numerous occasions. Is not this longing justified? Is there anything untoward about it? Of course not.
God, like us, has emotions, and he is grieved by the unfaithfulness of his creatures. By contrast, the gods of the heathen nations surrounding Israel were not grieved by the behavior of a people; rather, they felt only a capricious and unpredictable anger and expected to be placated by various and heinous perversions of the meticulously proscribed rituals carried out first by the patriarchs at various altars, then by the Aaronic and Levitical priests in the moveable tabernacle, and then later still in Solomon's temple and its successive rebuilding.
In Jeremiah chapter three, which begins with a husband divorcing his wife and the wife giving herself as a harlot to many lovers, the husband in hope against hope thinks that surely his wife, once she has had her fill of her numerous but ultimately unsatisfying lovers (notice the introduction of draught into the imagery in v.3, a symbol perhaps of spiritual thirst which cannot be slaked apart from God's living water) will eventually come to her senses and return to him.
Even Judah, having had a chance to learn from Israel's mistakes, also played the harlot, making her abandonment of her one true God even more despicable. Israel may have been faithless (vv.6, 8, 11 and 12), but Judah proved herself to be treacherous (vv. 7, 8, 10, and 11), thus proving Israel to be more righteous(!) than she. (Historical note: Samaria, Israel's capital city, fell in 722 BC, which began the Assyrian deportation and captivity; whereas Judah whose capital city was Jerusalem fell in 586 BC, which began the Babylonian captivity. Judah obviously did not learn from Israel's negative example which she set some 136 years earlier.)
We could go on to other prophets who used the marriage covenant as an analogy for the relationship between God and his chosen people (e.g., the prophet Hosea), but we need not labor the point. Each passage has this in common, however:
God rightly expects his people to honor the covenant between him and them. He feels poignantly their failure to honor that covenant as they play the harlot with gods who are not God. Moreover, those feelings are all the more poignant because those harlotries are committed not just by a monolithic nation but also by a people consisting of literally millions of individuals, from the king and his family and the Aaronic and Levitical priests and their families, right on down to the lowliest peasant and even the sojourner among them. Each citizen is, in a sense, one faithless and treacherous wife, which multiplies God's sorrow a million-fold when contrasted with the sorrow of just one earthly husband.
In conclusion, the Bible's anthropomorphisms, though perhaps at times woefully inadequate in communicating to us the spiritual realities and truths behind them, have nevertheless been given to us by God as object lessons through which we can be taught many valuable lessons as to the character of God and the way in which he wants us to live before him as his beloved chosen ones as well as his lights and representatives before a watching world.