Kaa-san ga Tou-san ni wa Mottainai hodo no Bijin datta node Netotte Jibun no Mono ni Shite 1-nengo | 妈妈是爸爸配不上的美女所以我把她睡到了手一年后

话虽如此,突然听说这些您一定很困惑吧所以我来为迟钝的您从头捋一遍虽然爸爸您好像毫无察觉,我和妈从母子变成男女关系是在距今大约三年前

Having said that, you must be confused when you hear all this suddenly. So I will explain it all to you from the beginning. Although you seem to be unaware, my mother and I changed from mother and son to a man and woman about three years ago.