Max, you're reducing his armor by 24%. 90 bonus armor plus however much base armor he had at whatever level you two were at, and all you've reduced is maybe around 40 armor? Which means he's still got plenty to handle you. And he's got two defensive items to your one offensive item.
Now you've got nothing but your base MR to handle his offense. His damage is magic, and he's hitting you with presumably a full W and by what you said below, you're not dodging it, you're tanking it for some reason? So yes, you're eating all of his damage for free with no legitimate defenses, while he's eating all of yours but with the defenses to not really have to worry about it.
This is fine.