YOU SAID:

We had to switch pants because i wet mine

INTO JAPANESE

濡れたのでズボンを交換しなければなりませんでした

BACK INTO ENGLISH

I had to change my pants because it got wet

INTO JAPANESE

ズボンが濡れたので交換しなければなりませんでした

BACK INTO ENGLISH

My pants got wet and had to be replaced

INTO JAPANESE

ズボンが濡れて交換しなければならなかった

BACK INTO ENGLISH

My pants got wet and had to be replaced