The biblical claim used for this is Matthew 5:28 "But I say to you that everyone who looks at a woman with lustful intent has already committed adultery with her in his heart."
For me it's clear we should love all sinners with the same grace Christ shows us, but with marriage everyone has the right to set their own standard. Don't get me wrong if no one meets it that's on you. However after seeing two post on r/TrueChristian where a guy wants to marry a virgin got trashed it caused me to wonder. How should guy's respond to women that might say you watching porn 10 times is the same as them sleeping with 10 guy's or even you watching porn 100 times is the same as them clubbing with a body count of 100.
It might be said a counter to this verse being applied to a marriage situation is 1 John 3:15 "Whoever hates his brother is a murderer, and you know that no murderer has eternal life abiding in him."
No one would shame a Christian for not marrying a person that committed murder despite the fact every single one of us has hated a person before. Yet it's become acceptable to shame for wanting a person that made some effort to follow God's commands even if they aren't truly sexually pure by masturbation or porn. Getting to my point not fornicating is much easier than not lusting to images. You can just flee whenever close to a person you might bang, but when your mind is burning it matters not where you go. You can't chop off your own head without dying and so fleeing in the flesh at best means cutting off your hands plus removing your eyes. A much higher bar to clear than just walking away. Because of this I feel it's illogical to compare the two act's being always directly equal.
This whole ordeal also made me wonder about guy's that have used escorts and hookers. By this standard of men accepting non virgin women due to having used porn should women with sexual history be shamed into accepting men that used hookers? How should Christian women deal with guy's that have traveled overseas to pay for sex and then repented of it?
Stats for the rules: Height: 6'1'' Weight: 181 Age: Mid 20's