The relevant rule is section 32(2) of the Visa Code:
A visa shall be revoked where it becomes evident that the conditions for issuing it are no longer met. A visa shall in principle be revoked by the competent authorities of the Member State which issued it. A visa may be revoked by the competent authorities of another Member State, in which case the authorities of the Member State that issued the visa shall be informed of such revocation.
So what it comes down to is whether the fact that you would be staying with your (then) girlfriend was a determining factor in the decision to approve your visa. This would usually only be the case if you couldn't have afforded the trip otherwise.
Even in the worst case, it seems to be unlikely that the Dutch authorities would revoke your visa without communicating with you first. But it is possible that they'd put a note on the visa/passport such that border guards would be more likely to probe into your means of subsistence when you enter. So you might want to be extra sure you're traveling with good documentation of your plans for food and lodging during the planned visit.