As @k.h.p. put it, the law is without emotion in this regard, and to be blunt, your opinions on marriage are irrelevant from IRCC perspective.A. Because it sounds like Marriage is “the only” option which is suppose to be not. Were people saying “Get married and or you should have gotten married instead”
It's fairly simple: spousal sponsorship is to sponsor spouses. If you're not spouses (by marriage or by common law), you are not eligible. Period. The only exception - conjugal sponsorship - is for those who are prevented or face insurmountable obstacles to becoming spouses. That does not appear to be the case. If you don't meet those criteria, spousal sponsorship does not apply and there's no 'planning to be spouses' program.
As I understand the law in UAE has been reformed to allow you to cohabit, and you are now doing so, the logical outcome will be a refusal for the reasons above and that you are not yet common law; effectively, you applied too early - you could have simply waited until you had the requisite 12 months of cohabitation. (If I understand correctly, one of you was in the Netherlands before that, so you won't really be able to claim that you were prevented from living together at that time, or factually living together despite the law prior to November - but I do not know the details of your timeline).
On the positive side: although I don't think there's any basis for the conjugal application to be approved (but perhaps it will, not my decision), in your particular circumstances, the refusal might not be a strong negative factor in future. When you re-apply later - either as common law or as married - you should explain that your previous application under conjugal was refused but that now you meet the spousal sponsorship criteria as married or common-law.
Again frankly - when re-applying in future, admit that you made an error in applying under and believing you qualified as conjugal and now are applying having met the criteria for spousal sponsorship. It likely will get some extra review (probably all previous refusals do). But at least in your case the refusal will likely be for a clear and obvious reason which can be easily corrected - by meeting the requirements for spousal sponsorship.
Note, this is crucially based upon you being able to reside together for 12 months continuously and being able to document this fully and carefully OR getting married before re-applying.