Wife and I compromise.
Granted I may not love my keyboards as much as you guys do, but I have personal expenses that I need to take care of too. Recently I've invested in a nice set of PBT keycaps (which should arrive shortly!), customized StarCraft II keycaps, new mouse, new gaming surface, new headphones and even a brand new rig that I built myself.
In the meantime, she's bought loads of shoes, bags, and makeup.
We're both happy, both satisfied, and we're living within our means and budget.
The important thing to keep in mind is for both of you guys to know that you have your own hobbies and they should be respected. While I'm not necessarily a big fan of my wife getting more shoes/bags/makeup (what's wrong with the stuff you have now?!), I understand that for women it's an accessory in the same way new gear is for us. She probably feels the same way about my computer and gaming gear.
We still respect each other's decision, and we don't knock each other for buying new stuff. We each see how getting these new toys make us happy, and isn't that what we want for each other?
Always communicate with your spouse and let them know what's up. If you're planning on a purchase, let her know. No need to be sneaking around as that could cause trust issues and lead to bigger problems. There needs to be a mutual understanding of you both having your own thing, and the other should respect that.
tl;dr - Compromise. Respect. Communicate.