I would hate if my husband was trying to micro manage grocery shopping!
I don’t understand how €800 could be spent on groceries in one week. As a family of 5 (4 adults and a teenager), I’d spend about €120 on a Big shop, and about another €25 on top ups of milk, bananas etc. However I know we buy a lot of Supermarket Own Brand items, and we tend to eat mince rather than steak! It would be easy to spend a lot more if buying expensive brands, shopping at M&S, or upmarket local delis etc.
From reading all the posts, I wonder:
Does your wife work? Has she ever worked? Has she ever had to manage her own money?
Is she aware of the Big Picture regarding your family finances?
Is she Irish? If not, does she have good English? Is she entitled to work in Ireland?
Do you have kids?
If she has never had to manage her own money, maybe she just hasn’t learnt how. Depending on her background, she may not have received good example.
I have a family member who grew up in a wealthy family, but even though his circumstances have changed, he still often has extravagant tendencies, which is wife is able to reign in!
I have another older family member, who was at home full time. She never knew what her husband earned. She had access to money through cheque books etc, but had no idea of the big picture. She would worry if her husband made a big purchase, because she had no idea whether they could afford it. On the other hand, he would talk about his thriftiness regarding other purchases. So she was getting mixed messages. She was very sensible with money as it happens.
I would hope that your wife could manage her spending better if the 2 of you do some budgeting together, so she can see the big picture.
If she is shopping because she is bored or lonely, maybe she needs support to find friends or social outlets (especially if she is living a long way from her family). Volunteering, joining a gym, language classes or similar could be a good start.
Someone else mentioned cash back. If she is accumulating cash it could be for a large number of reasons, such as sending money home, gambling, or building up ‘running away’ money.
Maybe the grocery shopping includes alcohol and she is drinking?
All in all, this is a very intriguing thread! Good luck with managing this - it could be tricky to do without causing huge offense and upset.