mytake, there are so many different opinions on tznius. Most frum women do fall in with the most lenient opinions out there. That’s why its hard to take the “if only that woman would cover her knee 100%, I wouldn’t be tempted” complaints seriously.
When you walk down the street, you see plenty of women scantily clad. If the frum woman who’s skirt is mid knee is bothering you, it has nothing really to do with what she is wearing and more to do with your own issue.
And that is aside from which, just because a woman is doing the wrong thing, doesn’t mean it gives the man the right to transgress.
If a woman is a moredes and the man is struggling, he should try to fix the problem that caused the woman to be a moredes. Or seek divorce if that’s unworkable. He shouldn’t blame the woman.