This interpretation I am providing is Rabbi David Fohrman's from alephbeta.org
The problem with looking at the Biblical stories is that we often read them quickly, and we know how the story ends before we've even read it, both these things color how you interpret the actions of the characters. But if you slow down and don't insert any commentaries into what's happening, you can see things in a much more different (and arguably correct) way.
ו וְרִבְקָה, אָמְרָה, אֶל-יַעֲקֹב בְּנָהּ, לֵאמֹר: הִנֵּה
שָׁמַעְתִּי אֶת-אָבִיךָ, מְדַבֵּר אֶל-עֵשָׂו אָחִיךָ לֵאמֹר. 6 And
Rebekah spoke unto Jacob her son, saying: 'Behold, I heard thy father
speak unto Esau thy brother, saying: ז הָבִיאָה לִּי צַיִד
וַעֲשֵׂה-לִי מַטְעַמִּים, וְאֹכֵלָה; וַאֲבָרֶכְכָה לִפְנֵי יְהוָה,
לִפְנֵי מוֹתִי. 7 Bring me venison, and make me savoury food, that I
may eat, and bless thee before the LORD before my death. ח וְעַתָּה
בְנִי, שְׁמַע בְּקֹלִי--לַאֲשֶׁר אֲנִי, מְצַוָּה אֹתָךְ. 8 Now
therefore, my son, hearken to my voice according to that which I
command thee. ט לֶךְ-נָא, אֶל-הַצֹּאן, וְקַח-לִי מִשָּׁם שְׁנֵי
גְּדָיֵי עִזִּים, טֹבִים; וְאֶעֱשֶׂה אֹתָם מַטְעַמִּים לְאָבִיךָ,
כַּאֲשֶׁר אָהֵב. 9 Go now to the flock, and fetch me from thence two
good kids of the goats; and I will make them savoury food for thy
father, such as he loveth; י וְהֵבֵאתָ לְאָבִיךָ, וְאָכָל, בַּעֲבֻר
אֲשֶׁר יְבָרֶכְךָ, לִפְנֵי מוֹתוֹ. 10 and thou shalt bring it to thy
father, that he may eat, so that he may bless thee before his death.'
There is absolutely no indication from her words/commands to Yaacov that she had any intention of tricking Yitzchak. All she said to do was to go get two goats in hopes that she could prepare them, and then Yaacov could bring them to Yitzchak before Esau got back so that way Yitzchak might decide to give the blessing to Yaacov instead. Read the text over and over again, and you will see nothing nefarious in her words. However, Yaacov's response to them is very interesting.
יא וַיֹּאמֶר יַעֲקֹב, אֶל-רִבְקָה אִמּוֹ: הֵן עֵשָׂו אָחִי אִישׁ שָׂעִר, וְאָנֹכִי אִישׁ חָלָק. 11 And Jacob said to Rebekah his mother: 'Behold, Esau my brother is a hairy man, and I am a smooth man.
יב אוּלַי יְמֻשֵּׁנִי אָבִי, וְהָיִיתִי בְעֵינָיו כִּמְתַעְתֵּעַ; וְהֵבֵאתִי עָלַי קְלָלָה, וְלֹא בְרָכָה. 12 My father peradventure will feel me, and I shall seem to him as a mocker; and I shall bring a curse upon me, and not a blessing.'
יג וַתֹּאמֶר לוֹ אִמּוֹ, עָלַי קִלְלָתְךָ בְּנִי; אַךְ שְׁמַע בְּקֹלִי, וְלֵךְ קַח-לִי. 13 And his mother said unto him: 'Upon me be thy curse, my son; only hearken to my voice, and go fetch me them.'
יד וַיֵּלֶךְ, וַיִּקַּח, וַיָּבֵא, לְאִמּוֹ; וַתַּעַשׂ אִמּוֹ מַטְעַמִּים, כַּאֲשֶׁר אָהֵב אָבִיו. 14 And he went, and fetched, and brought them to his mother; and his mother made savoury food, such as his father loved.
טו וַתִּקַּח רִבְקָה אֶת-בִּגְדֵי עֵשָׂו בְּנָהּ הַגָּדֹל, הַחֲמֻדֹת, אֲשֶׁר אִתָּהּ, בַּבָּיִת; וַתַּלְבֵּשׁ אֶת-יַעֲקֹב, בְּנָהּ הַקָּטָן. 15 And Rebekah took the choicest garments of Esau her elder son, which were with her in the house, and put them upon Jacob her younger son.
טז וְאֵת, עֹרֹת גְּדָיֵי הָעִזִּים, הִלְבִּישָׁה, עַל-יָדָיו--וְעַל, חֶלְקַת צַוָּארָיו. 16 And she put the skins of the kids of the goats upon his hands, and upon the smooth of his neck.
יז וַתִּתֵּן אֶת-הַמַּטְעַמִּים וְאֶת-הַלֶּחֶם, אֲשֶׁר עָשָׂתָה, בְּיַד, יַעֲקֹב בְּנָהּ. 17 And she gave the savoury food and the bread, which she had prepared, into the hand of her son Jacob.
According to the plain reading of the text, it was Yaacov's idea to dress up like Esau and trick his father, not Rivka's. But we do see that Rivka decides to go along with Yaacov's plan, and she even tries to take responsibility for it to encourage him to do it, but again her focus is always on cooking the food.
This is why the words in verse 45 stand out to you. She says "what you did to him" because her original plan had nothing to do with tricking Yitzchak or pretending to be Esau, those things were entirely Yaacov's plan. When you read the story this way, future events are easier to understand, such as why Yaacov is continuously punished for his deceit moreso than Rivkah, and why Laban isn't punished by Hashem for having deceived Yaacov, because Yaacov was receiving his due punishment for what he had done.