Ok, here is what has worked for us over the years. Your mileage may vary.
Now I will say it's been an educational experience for me over the years.
I can remember vividly at our beginnings and even the first pinball "blow up" with my wife.
We were newlyweds, it was almost 15 years ago, at the time I only had 1 pinball a DE Simpsons Pinball. We went out for Valentines and over dinner I brought up in conversation that I wanted another pinball....a Black Hole I had called on from an ad in the Thrifty Nickel up in Oklahoma. She about flipped! "You want ANOTHER ONE!"
Over the years it has gotten better. Not to say that we haven't had several arguments over my hobby over the years. Some I've won, some I've lost. But through it all we still love each other and as much as she sometimes may think pinball is more important than her, she's wrong. She is #1.
One thing that we've done to keep things in line with my pinball obsession. Is that many years ago I opened my own checking account. This account I use for all of my pinball fun money. It is completely separate from either of our pay checks and it in no way is supplemented by our incomes. It is the account I use for my parts and machine buying, game selling etc. Pretty much if the money isn't in this account...then I can't buy it. We had problems years ago where although I would write a big check to Pinball Resource for $200 out of the main account she was freaking out, "you spent $200 on pinball parts!"While a day or two later I would reimburse what was taken out from selling a game, doing a repair, etc. Now this isn't an issue anymore as I only buy parts from the funds I have segregated into my pinball account. She really doesn't know what I spend on pinball parts now a days as it's coming from my own pinball checking account. It's no secret though, she's welcome to look at it. I just keep it separate from our main checking account to avoid confusion.
Jared don't worry your not alone. My wife is like yours and many others and doesn't really care about pinball. She refers to herself jokingly when I'm cranking games out for customers, the aution or the Texas Pinball Festival as my Pinball Widow. I ask of her patience during these times, and many times I try to reward her with something for putting up with the crunch time. Example being I cranked 4 games out for repairs to customers as well as a few I sold at the last auction. I was burning the midnight oil a couple of weeks ago trying to get these games ready. She was getting frazzled that I was spending so much time on the games. In the end I've made it up to her, as some of you know she is a kindergarten teacher and I made it up to her buy giving her $200 toward buying herself some new clothes for this school year. We're also going school clothes shopping for the boys this weekend, I'll help out with this pinball money too.
She's supportive of the fact that I have a hobby I enjoy, but she doesn't care for it as she isn't much of a player. I think she has played our AC/DC Pinball 3 times and I've had it for several months now. In the same regards, she loves scrapbooking........I could care less about them. But she enjoys making them and I'm supportive of her hobby and I like looking in her books she has made of our boys.
All in all, I think the best advice I could give is try to be balanced with it. As much as I love tinkering with my machines, I try to balance family time too. Which at sometimes is hard (as stated above getting games ready for the TPF). Also don't hide anything, be open about what your buying and why. This part may be easier for me as I've made a lucrative side business of buying, selling and restoring games for customers over the years. Without the selling and repairing of games I do for customers, my hobby couldn't exist as it's all self sufficient.
Thats my .02. Hope it helps.
Happily married to a Pinball Widow of 15 years now