We are married and have separate accounts our salaries go into, and also a joint account and joint credit card. We put enough into the joint to pay bills, although as my dh earns nearly 3 x what I do he puts in more, although it's not worked out to a formula.
Until we had children we kept finances fairly separate, but since having children, and unpaid mat leave and then I worked part-time to spend some family time with the children, everything belongs to both, up to a point. Food shopping, children's clothes, clubs etc come from the joint account. We still both like to have our own accounts so we can buy presents etc.
We both save each month too, but when we want to buy something big - extension etc, then we both put in money.
We have similar approaches to money, and although he earns more than I do, we are actually both on good salaries so money isn't tight (but we're both fairly cautious spenders). I think that helps.
As for taking people out for dinner - until we had the children that would come from our separate account, but these days although one of us might invite the other, we know the money's coming from a joint pot really. If we're going somewhere v expensive then we need to agree before hand that we're going there and have a good reason.
During mat leave I saved most of my salary during the first 6 months paid instead of putting it in the joint, and then used those savings for the final 6 months. Child stuff came out of the joint account, but I didn't want to feel I had to ask for more money when I wasn't being paid, so can just use my account. It's psychological really.