I would say it's a matter of justice. The goal of marriage is to raise Godly children and help your spouse get to heaven. There are certain topics that should be discussed before hand. Would you not discuss the crisis of the Church beforehand? If one spouse thought the new rites were valid and the other did not, and if their traditional priest got replaced by a NO priest (possible in SSPX) then there is now a huge problem of moving somewhere else for valid mass and Sacraments with disagreements between the spouses.
Likewise a person's 'past' may be important to the other potential spouse. As a man I wouldn't be happy knowing my wife got deflowered by another man, has had sɛҳuąƖ relations with others, can't bond with me like previous partners, microchimerism and telegony, psychological imprint by the other partners and emotional baggage, etc and other worse things I won't mention.
That would be extreme cope. Also a women may desire her husband to be hers and hers alone (can't list reasons like above because I'm not a women).
I've heard it said.
A women is judged by her past, a man by his future.
Afterall a man's virginity isn't going to put food on the table and pay the bills. Still if a virgin women demands a virgin husband that is fine, people have their preferences and baseline standards.
Choosing not to discuss these things is foolishness, you do not want to marry the wrong person and end up in hell. If you find out something after getting married that bothers you a lot then it's going to make things unnecessarily harder, at the expense of your souls and your children's souls when it could have been easily avoided by taking before marriage.