Can I ask: why should you curb it? Do you have money problems? Because, the way I see it, if you can afford it, then go, friend.
The fashion industry is the second most polluting in the world. Insane amounts of water, energy and chemicals - not to mention slave labour - are used in its production.
The sea is full of microplastics, a significant amount of which is from us washing our plastic clothes (polyester, viscose etc) which releases microscopic fibres. Apparently we all have a credit card's worth of plastic inside us from ingesting water and seafood.
Our love for fast fashion means that shops like Zara, H&M etc race to produce a huge number of poorly made or ill thought out "lines" inspired by what magazines and influencers tell us is in fashion, and this means thousands of tonnes of never-bought, let alone worn, clothes are sent to landfill every year.
By buying into the fashion cycle sold to us by glossy mags and now Instagrammers (ie getting sucked into feeling what you already own is inadequate or that you can't be seen wearing the same dress three times by the same friends or that your clothes are "last season" or whatever) you are enabling this.
If that's not enough to make you think twice about buying something new when you've already got a wardrobe full of perfectly good clothes, then OP - can I gently suggest that new clothes will only buy you confidence momentarily, and as soon as it no longer feels new and shiny and gorgeous you'll need your next "fix". Much much better for you and the planet to invest in inner confidence.