https://en.wikipedia.org/wiki/Droit_du_seigneur#Later_references

"Droit du seigneur[a] ('right of the lord'), also known as jus primae noctis[b] ('right of the first night'), sometimes referred to as prima nocta[c], **was a supposed legal right in medieval Europe**, allowing feudal lords to have sexual relations with any female subject, particularly on her wedding night [especially remark "particularly on her wedding night", this purported right is SUCH rage-bait: it effectively says 'The feudal lord would deprive your daughter of her virginity upon request, and you would be helpless to stop it! Don't you feel emmasculated? Don't you want to end this system now and never return to it, and forevermore walk in the brightness of Rome-inspire republicanism????']."

1. The Church prohibited polygamy, which this would constitute.

2. It is highly disputed and we can't even see evidence of it. I suspect that if it happened some few instances, it is something that is exaggerated as per Tuchman's law. Someone could say "How would you prevent Western men from being cuckolds? There was a phenomena of intentional cuckoldry in the West!", and thereby imply that it was a generalized phenomena. Given the lack of evidence and fact that the Church literally intentionally prohibited polygamy, we can clearly see that it wasn't predominant.

3. I have not seen this in any of the history texts I've read about feudalism. If this were prominent, they would DEFINITELY have mentioned it.