My wife and I have separate accounts and we have divided up the bills. We have done this since we have been married...since 1975. When we were bringing up the kids and paying off our mortgage, extra cash was hard to come by. The last decade or so have been different and I try to tuck aside at least $50 a week for as long as I can for future toys. Put I away and forget about it and live within my means otherwise. Some weeks I can save more but it's always at least $50.
That's how I have obtained my guitars, guns and other fun stuff. I don't have to ask permission so long as I keep her happy with dinners, movies and other fun stuff. Every once in awhile she will put something in the safe and will notice the growing gun collection and will ask me how many guns I have bought lately. I tell her I have no secrets, all she has to do is count them and keep track. I'm not sure if she has done it or not. Hey it works for us!