If the court ordered that a QDRO be done, it should be done.
If you are the one who is supposed to benefit from it (i.e. get benefits from your spouse's 401K or retirement plan), then by not doing it, you are losing out on those benefits.
If you are the one who owns the 401K or retirement plan, you'll make out like gangbusters if no QDRO is done because then you get all of those funds.
However, your ex could sue you for your failure to do the court-ordered QDRO and thereby providing him/her the benefits that had been ordered by the court.
Your post didn't include enough facts for me to really give you any other comments on your situation.
