Okay, i've been thinking a lot about "The Bride of Frankenstein" as a character in the original novel, and something i see people mentioning a lot is that Victor could have just made the Bride sterile if he was so afraid of the two monsters reproducing. But i have to say, even if he did finished the Bride, let's call her Elsa to make things easier, and sterilized her by not giving her an uterus, things would still end badly, for him, the Monster and the Bride.
Let's ignore the big posibility of Elsa not liking her intended husband, The monster/Adam. Because one of the reasons why Víctor decided not to finish Elsa was because he realised that just because he made Adam a bride, it didn't mean that she will like him.
But let's say that the two creatures get alone great and fall in love with eachother, that Elsa is happy with being Adam's wife, so Adam keeps his promise and leaves Victor and Elizabeth alone, runing away with Elsa.
There is a big posibility of them eventualy wanting a child of their own. Adam's (very limited) knowledge of women comes from the Bible, he knows that the union between a man and a woman usually leads to them having a baby, and i don't think he would be oposed to having children. Since he asked Víctor to make him a Bride so he wouldn't be alone anymore, he might see kids as something that naturaly comes with having a wife.
Now, Adam could bring this up to Elsa and 2 things could happend:
1) Elsa wouldn't be on board, she could love Adam very much but still not want kids for whatever reason and this could make Adam angry/disapointed. They could still be toguether or they split, and if the second happends, then Víctor's fears of having two lonely monsters to deal with comes true. This might even lead to a Lilith/Eve situation where Adam looks for Victor again and demands another bride, one that is willing to have kids with him.
2) She could totally like the idea of having a kid with Adam and becoming a mother, Adam is happy and both of them are exited. But after a while, they are still childless and decide to look for Victor again. Now, Víctor could either tell the truth saying that he chose to make Elsa unable to have kids or he could lie and say that for whatever reason, they couldn't have kids.
Imagine how angry and heartbroken Elsa would be after hearing that the choice of having a child was striped away from her, just because her creator didn't like the idea of having more creatures around. Her and Adam might demand that Víctor "fix this" by making them a kid or could take revenge on Víctor by killing Elizabeth like in the original novel. Even if Víctor lied about why they can't have kids, nothing is stoping the couple from demanding that he makes them a kid or two. How many kids would they want? 2? 4? 6? How many kids would Víctor have to make for them?.
I think my point is clear right? Removing the Bride's ability to have kids doesn't remove the posibility of things not working out for her and the creature, even if they end up liking eachother and chose not to have kids regardless if they can or can't have them. They will still be outcasts and will be seen as monsters by society, life will still be dificult even if they have eachother and nothing guarantes that their relationship will last.
Victor might not have considered all this scenarios but what he did consider was enough to make him realise two things: The Bride will have a mind of her own, she'll have agency just like The Creature, and there is no actual guarante that she will want to be the Eve to his Adam. And he would be making the same mistake twice, playing God and bringing life to something that shouldn't be alive in the first place, a creature that will most likely be miserable because it doesn't fit in society.
There is a reason why the movie "Bride of Frankenstein" ends the way that it does.
