Is this fair - contribution to household

[Dobbycraft]

We've had the arrangement for a while and I've always been happy with it, but a family member seemed shocked and thought it was unfair and now I'm questioning it.

We put £3200 in to the joint account each month to cover the mortgage, all household bills, food and family expenses and any left over goes in to family savings. (Neither of us have ever wanted to put it all in to one pot, we like having personal money)

Person A:
Works full time, take home pay varies between £3000-£3500 per month.
Puts £2200 in to the joint account each month.

Person B:
Works 3 days (plus 2 days at home with a toddler) take home pay is around £1350.
Puts £1000 in to the joint account each month.

Is this pretty fair considering neither person is wanting to put it all in one pot?

If I was B, I'd want a little bit more than £350 a month of 'fun' money to even it up a little but I wouldn't get worked up about it particularly. DH and I have different amounts of personal spending money each month due to the difference in our salaries and what we have left after we've split costs pro rata but I've never seen it as a big deal really. If you're happy and it's working for you, it's not really anyone's concern. I do also find that there's always a divide between joint pot people and separate finances people and often they can't understand why anyone would do the other!