Dic: for better or (for) worse; for better, for worse

• I married you for better or worse, knowing all about these problems.
• For better or for worse, I'm going to quit my job.
• We cannot deny that our childhood experiences affect us, for better, for worse.

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1. If you say that something has happened or been done for better or worse, you mean that you are not sure whether the consequences will be good or bad, but they will have to be accepted because the action cannot be changed.
2. under any conditions; no matter what happens
3. if a situation exists or happens for better or for worse, it exists or happens whether its results are good or bad

Usage notes: This phrase is used in a traditional marriage ceremony in which the man and woman promise to stay together whether their life is good or bad.

.... Cobuild, McGrow-Hill Idioms, Cambrdige Idioms