It might. I think the line that “it’s very difficult and many men struggle with it” and that she’ll have a hard time finding a man who doesn’t struggle with porn is a bit counter-productive. People wouldn’t say this about alcohol addiction or if he was sleeping with different women while also preparing for marriage.Walking away from the man they love is not going to help that man stop using porn.
Are you better in a marriage that is damaged by porn/alcohol use than no marriage?
I’m not claiming to come from a position of always having been perfect but I know for a fact that it’s possible to come from a place of regular sexual sin, to zero sexual sin. Sure, it’s a struggle, but it’s not impossible. What needs to be determined here though is if this particular case is bad enough to warrant the OP reconsidering the marriage.
If he’d renounced porn then and there on the spot, while I may not believe that he’d never fall again, I’d be more inclined to think that he’s at least trying. But I don’t get that impression.
There is a grace in marriage that helps us to overcome our vices but the problem is that it needs to be worked upon before the marriage starts. Other things to look at would be does he pray regularly, what steps has he gone to to eliminate porn from his life thus far, and indeed, does he even see it as a major problem.
There are definitely catholic men out there who don’t view porn on a regular basis, and I don’t think they’re as uncommon as we’ve been led to believe.