I always end up having an argument with her, I don't know why, I just can't help it.

我总是和她意见不合，闹得不欢而散，我不知道为什么，我就是忍不住。

《牛津词典》

I don't want to do stupid things but I just can't help it.

我不想做蠢事，但我就是不行。

youdao

I knew I shouldn't eat too many sweets, I just can't help it.

我知道我不能吃太多的甜点，可实在是忍不住。

youdao