YOU SAID:

you may have thought I was joking but I would not have done such a thing had I not checked first

INTO JAPANESE

もしあの時、彼が私と一緒にいてくれたら、私はあんなことはしなかったのだが。

BACK INTO ENGLISH

If he had been with me then, I would not have done such a thing.

INTO JAPANESE

もしあの時、彼が私と一緒にいてくれたら、私はあんなことはしなかったのだが。

BACK INTO ENGLISH

If he had been with me then, I would not have done such a thing.