CathInfo.com

Also if someone has viewed pornography intentionally even ONE time it should be disclosed.  Why?  Because pornography use by men has the similar effect against pair-bonding that pre-marital sex has on women.  We have been told by our priests that one use of porn can destroy a man's natural attraction for real women for life.  Every woman has a right to know if her potential spouse is a habitual self-abuser.  That will ruin a marriage.

If every trad followed your advice, then no trad marriage would ever happen again or... porn usage will be increasingly publicly normalized in trad circles because of the commonplace admission of committing the sin. I do not calumny trads when I say that 95% of trad men have viewed pornography "even one time" in their life. Multiple trad priests said that the #1 and #2 confessed sins from men in the twin sins of viewing pornography and self-abuse. Put yourself in their shoes: they have strong desires as young adults but moral qualms against fornication and adultery. 
Also, where do you draw the line at pornography? MTV music video? A PG-13 movie? Sports Illustrated Swimsuit Edition? Sears catalog?
Why not demand that if someone has self-abused even one time it should be disclosed? 
Why not demand that if someone has entertained impure thoughts even one time it should be disclosed? 

Maybe you should have been a priest if you want people to confess everything to you.

Oh, and if I were a young lady, I would definitely do my DUE DILIGENCE and look into the man's past. Look him up on social media, pose as a high school friend and see what you can find out, etc. I'd probably pay the $30 or $60 fee to do a background check. Or a few hundred dollars for a private investigator. Think that's excessive? You can't be too careful these days. We're talking about avoiding a life of misery, loneliness (divorced but can't remarry), poverty, strife, etc.  I think a few hundred dollars would be well spent to avoid that! Oh, and as a bonus (since you never married "the wrong guy"), you might also GET a nice Catholic man, loving family, beautiful Catholic household, many beautiful well-raised Catholic children, grandchildren, etc. as a bonus! A few hundred dollars sounds like a bargain now...

What about medical proof the fiancé's not impotent or the fiancée's a virgin?

This is the question of self-detraction:
McHugh & Callan Moral Theology:Thus, no, the "potential spouse" has no "right to know sɛҳuąƖ history before marriage".

Claudius should not deceive Sempronia, nor leave her in ignorance of any serious objection to the marriage, even if she forgot to mention it in her questions; but he owes it to himself not to put himself in her power by giving her information which she would probably use against him then or later.

Interesting.  I read the bolded (and underlined) differently.  To me, it sounds like McHugh and Callan are saying he should tell her something as serious as one's sɛҳuąƖ history before marriage BUT not to tell her things that she would use against him.

I would say that if there is even a hint that Sempronia would use that information against Claudius, then they already have bigger problems than his previous sɛҳuąƖ history and probably shouldn't get married anyway.