Our Gemara discusses an instance where a man seems to express a change of heart regarding divorce, but his language is unclear:

גִּידּוּל בַּר רְעִילַאי שַׁדַּר לַהּ גִּיטָּא לִדְבֵיתְהוּ אֲזַל שְׁלִיחָא אַשְׁכְּחַהּ דַּהֲוָה יָתְבָה וְנָוְולָה אֲמַר לַהּ הֵא גִּיטִּיךְ אֲמַרָה לֵיהּ זִיל הַשְׁתָּא מִיהָא וְתָא לִמְחַר אֲזַל לְגַבֵּיהּ וַאֲמַר לֵיהּ פְּתַח וַאֲמַר בָּרוּךְ הַטּוֹב וְהַמֵּטִיב

The Gemara relates: A man named Giddul bar Re’ilai sent a bill of divorce to his wife. The agent went and found that she was sitting and weaving [navla]. He said to her: This is your bill of divorce. She said to him: At least go away from here now and come tomorrow to give me the bill of divorce. The agent went to Giddul bar Re’ilai and told him what had occurred. Giddul bar Re’ilai opened his mouth and said: Blessed is He Who is good and does good, as he was happy that the bill of divorce was not delivered.

אַבָּיֵי אָמַר בָּרוּךְ הַטּוֹב וְהַמֵּטִיב וְלָא בָּטֵל גִּיטָּא רָבָא אָמַר בָּרוּךְ הַטּוֹב וְהַמֵּטִיב וּבָטֵל גִּיטָּא

The Sages disagreed with regard to the status of this bill of divorce. Abaye said that he said: Blessed is He Who is good and does good, as he was happy that it was not delivered, but the bill of divorce is not rendered void through this statement. Rava said that he said: Blessed is He Who is good and does good, and the bill of divorce is rendered void.

Regarding this blessing, the Gemara in Berachos (59b) states: "For that which is exclusively his, he recites: Blessed…Who has given us life and sustained us; for that which belongs to him and to another in partnership, he recites: Who is good and does good."

״בָּרוּךְ … שֶׁהֶחֱיָינוּ וְקִיְּימָנוּ״, עַל שֶׁלּוֹ וְעַל שֶׁל חֲבֵירוֹ — אוֹמֵר: ״בָּרוּךְ … הַטּוֹב וְהַמֵּטִיב״.

The Chasam Sofer explains that in our Gemara, the husband used the phrase Hatov Vehameitiv rather than Shehecheyanu to emphasize Abaye's legal position. Despite the husband's happiness along with his wife that the delivery of the Get was delayed, it does not explicitly indicate a reneging on the divorce or nullify the agency of the messenger.

I will suggest another explanation for this choice of blessing in our Gemara based on a Be’er Mayyim Chayyim (Bereishis 46:13). He says that Hatov Vehameitiv emphasizes our gratitude and understanding that even events initially perceived as negative turn out to be for the best. The wording "good and does good" conveys the idea that God is inherently good, and even situations that may not initially appear good or welcome ultimately work for our benefit.

I will add another explanation for the husband’s choice of blessing, based on a Be’er Mayyim Chayyim (Bereishis 46:13). He points out that the Hatov Umeitiv blessing emphasizes that we are thankful and understand that even certain events that first appeared to be negative, turned out to be for the best. The language Tov and then Meitiv “good and does good” indicates this idea. God is good, and then even things that at first to not feel good, or are welcome, turned out to be for our benefit – “Vehameitiv” “and does good.” 

(I am not sure how the Be’er Mayyim Chayyim harmonizes his idea with the halakhic dimension that this blessing is recited when somebody shares the joy with you. Perhaps, it takes multiple people to have perspective that somethings that might seem bad now ultimately could be for the good? Or, that is the lesson in the blessing. When bad things happened, if you understood that the world is a partnership, then you would have a different perspective. That is it is easier to believe that this thing that looks bad is all for the best if you have God’s perspective on the interrelatedness of things. One bad outcome cannot be changed without it affecting an interwoven divine plan. This is alluded to in the famous story of Rabbi Eliezer ben Pedas who prayed to Hashem to extricate him from poverty. Hashem's answer was, “Do you think I should turn the world upside down from the beginning of time to allow you to become wealthy? (Taanis 25a)” The Tiferes Yisrael (Mishna Kiddushin 4:14) understands this Gemara to be saying, sometimes even for a great tzaddik, there is too much mazal and too many natural circumstances that cannot change the reality.)

In any case, this different way of interpreting the blessing, that it is recognizing the good there is to experience now, but also understanding the difficult circumstances prior were also for the good, gives us a new way to understand what the husband was saying in our Gemara. The conflict that brought us to the brink of divorce, perhaps was for a good thing, because it helped us resolve the problem and get back together. I relationships, after there is a major betrayal or some other breakdown, if a couple survives it, it leads them to insight and resolution of long-standing issues that were never properly dealt with. The result is that after the various empathic breaks and disappointments, the restoration can make for a stronger bond. As the Gemara Berachos (34b) tells us:

ואָמַר רַבִּי אֲבָהוּ: מָקוֹם שֶׁבַּעֲלֵי תְשׁוּבָה עוֹמְדִין — צַדִּיקִים גְּמוּרִים אֵינָם עוֹמְדִין, 

Rabbi Abbahu said: In the place where penitents stand, even the full-fledged righteous do not stand.

Why is this so? We can imagine that the experiences of disruption, and the process of change that it took to return, brings about a deeper and stronger bond with Hashem. So too in a marriage, when the disappointments and betrayals are healed, the connection is stronger than it was before.