This sounds like a troll post - but on the off chance it isn't: take it from someone who used to shit on people for wearing makeup, you're being a dick.

Money isn't an issue for us....she can technically do whatever she wants with it

Then actually let her do whatever it is she wants with it. It's one thing to be upset about a partner's cosmetic spending if it's really taking a toll on finances, but since this clearly isn't the case, your level of anger toward her is pretty unprecedented.

Makeup is not an art, it is simply vanity.

The point about it being art is debatable, but even if you don't personally think of it as having artistic standing, insinuating that makeup as a hobby has less merit bc it's tied to attractiveness is pretty dumb. There are so many hobbies that are just as 'shallow' - are people who are really into coins achieving some deep, profound meaning with their collection? Are people who are really into cars or computers shallow because the way an engine or keyboard feels matters to them? You're allowed to like things just because you like them - you're allowed to like things because they make you feel more accomplished, or more confident, or more entertained. I don't think anyone should be begrudged for their hobbies when all of us have our own interests, and ascribing away an interest with cosmetics as just sheer vanity is pretty unfair.

I'm sick of hearing about contouring and highlighting

Honestly this isn't a terrible point (though it's pretty harshly phrased). Listening to people constantly talk to you about things you're not even remotely interested in can be grating. But the thing is, there's always going to be something your partner is way more interested in than you are. And if you want to share your life with someone, you have to be willing to let them share that part of themselves with you too. I don't think people should be constantly talking about singular interests with their SO, so if you have a problem with it you could just talk to them and ask them to decrease the amount of conversation, but imo part of what's great about being with someone is watching them be genuinely interested in things, even if you're not. You love them enough to want them to be happy - it shouldn't really matter what's making them happy.

TL;DR: I doubt you're really divorcing your wife of 15 years over this. But if you are, I don't think you're the type who's ever going to be happy with their partner.