I can't get this manga out of my mind because it's funny to me. The seme fucked the uke with a banana? (on a stick). It was the festival and they were both wearing yukata. Then they both orgasm with fireworks in the background. Please don't judge me. xD
banana thing is from Yondaime Ooyamato Tatsuyuki
http://www.mangago.zone/read-manga/yondaime_ooyamato_tatsuyuki/mi/58e6b16270a430b4047c8f8d0102d3c7_chapter-11/1/
yakuta scene also like this one, but it wasn't the one you were after Himitsu wa Kiss de Abakareru http://www.mangago.zone/read-manga/himitsu_wa_kiss_de_abakareru/raw/tr_chapter-24.1/pg-1/
I guess since the ML experienced a bad childhood due to his parents, he wants to give the children time and take care of them as well as treat his wife good. But that heroine didn't see that and looked at him as a character in the story rather than empathize with him. Sadly the heroine didn't change and she probably didn't know what she did wrong.