earning the money does not give you any specific right about how it is spent - not over your partners right, in a true partnership.
my husband does not get an 'allowance' - we both agree expenditure in advance (though, probably we do manage with much less than £700 after bills, the amount isn't the point)
although we don't have a joint account - we always balance up together.
Now, where money is tight, that means discussing things like £20 for a new microwave, rather than £100 for a night on the tiles, but it simply wouldn't be fair if one of us (even if if it was I, the earner) was constantly splashing out and paying the other an 'allowance' - it wouldn't be fair.
As you control the food, i suggest you serve up Asdas delicious 9 pence noodles for dinner several nights in a row, and advise him you are doing this in order to keep within budget. Wash it down with £1.19 Smart Price cider and see if he feels like being more reasonable.
and not being married is not a good sign - is he afraid of the commitment (whilst having 2 kids and a house with you?)?