Well why didn't you just say so? That's a totally different question man!
I dunno how your marriage works, and how the money decisions are made, but in my experience the secret is just to make things feel equal. I'm not above buying my wife shoes and diamonds, redoing the windows in the house, whatever else makes it feel like I'm not just pouring money into my personal hobby and ignoring everything else. I know what she likes, I know her sizes, and I'll just get her treats when I feel like it's warranted.
Be smart about it. Take care of her needs too, and do it first. Not after you get a pin, like you're buying her off. More like "I think about you, not just my games".
You're never going to win the "get her into pinball so I can buy more" angle. Either she's already into it or it's probably a lost cause. So skip that and work at how you can carve out your own space for it while making her feel included in the thought process, not just the game side of things,