To answer the OPs original point. I make the money and make all of the major financial decisions, with input from the boys. BUT, they each have "fun money" that they don't have to account to me for and can spend on whatever they want (dating others, dating me, buying toys, etc.) This was well established before poly-dating was an issue. It has worked well for MrS and I for several decades and I advocate this approach! (We, jokingly, refer to this as "hookers and drugs" money!)
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With regards to the "who pays when dating" side discussion: In my world "Dutch" is the expectation unless someone is "gifting". (i.e. You are taking me out for my birthday or I am treating you to an experience that you wouldn't be able to afford.) Who asks whom is kind of irrelevant in my world - presumably it is a mutually agreeable positive or you wouldn't have accepted.
I am in the fortunate position to be able to afford to pay my own way (and the way of the boys) for anything I/we want to experience. If inviting our friends/lovers/potentials to experience those things with me/us makes it even more enjoyable then I will pay for them too. Or cover the excess, or let them treat, or whatever.
I think that the "traditional" expectation that "men pay" has a lot to do with the historical gender-gap when it comes to income (i.e. the person with the most money pays, men earn more money, therefore, men pay.) The fact that this has morphed into - "men pay for dates with the expectation of sex" - is an unfortunate side-effect, in my opinion.
Although, to be fair, I have never really "dated"

.
My (mono) BFF, SLeW, is currently actively dating to find "the one". She views dates as "free dinner with the possibility of sex...or more". The boys are paying for the privilege of her time/attention and the possibility of developing something else. Now, to be fair, she has other expenses to consider. Accepting someone's offer of a date involves her arranging for child-care (single mom) and whatever "girl-prep" she deems appropriate (outfits, makeup, hair-cuts, waxing - whatever "girly-girls" to do primp for a date

).