YOU SAID:
My girlfriend and I took a mutual break but then she started dating someone new right after
INTO JAPANESE
私のガールフレンドと私はお互いの休憩を取ったが、その後、彼女はすぐに新しい誰かと付き合い始めた
BACK INTO ENGLISH
My girlfriend and I took a break from each other, but then she immediately started going out with someone new
INTO JAPANESE
私のガールフレンドと私はお互いに休憩を取ったが、その後、彼女はすぐに新しい誰かと付き合い始めた
BACK INTO ENGLISH
My girlfriend and I took a break from each other, but then she immediately started going out with someone new
That didn't even make that much sense in English.