Ok don’t want to drip feed so context first.
DP works 3 days per week and has since before we met. Earns around half my salary, does 2 days pick up and drop off, also has some regular money coming in from old investments which is usually frittered away on clothes, buying meals for friends etc.
I work full time. Earn double his salary, pay at least 2 thirds of household costs/bills/shops/tickets/kids clothes and clubs. Am much better with money so have some savings which he is unaware of. Also save for DS who is 4 and has £7k in an ISA.
we have just booked holiday of a lifetime. I will pay for me and DS. DH will pay for himself. I have said I will also cover food and spending money for me and DS and have asked DH to sort himeself out. He is not frugal and likes nice things and so will generally choose the most expensive meal without considering the options (I will sometimes have a steak but would balance this out over the week with some cheaper options). He also drinks and I don’t. So there would be added cost for him of a few pints, cocktails or a bottle of wine (again no way would he chose a house bottle).
AIBU -
Y - you are a family and you earn more, you should split everything and pay 2 thirds.
N - he can fund his own drinks you paying for DS balances out the inequality in wages