YOU SAID:

I could've went to the party if it wasn't for you

INTO JAPANESE

あなたがいなかったら、私はパーティーに行くことができたでしょう

BACK INTO ENGLISH

I would have been able to go to the party without you

INTO JAPANESE

私はあなたなしでパーティーに行くことができただろう

BACK INTO ENGLISH

I could have gone to the party without you

INTO JAPANESE

私はあなたなしでパーティーに行くことができたでしょう

BACK INTO ENGLISH

I could have gone to the party without you