AIO or is my husband taking advantage of me financially?

My husband (we are both M35) lives in London for grad school (long distance). I paid his rent for a year. I also send him around 1,500 pounds each much to cover his cost of living. This would include his utilities and groceries. He usually cooks at home, and he sometimes uses my apple pay to pay for things like UberEats and odd purchases like coffee, and his transportation card (so maybe 300 - 400 a month total on my credit card). He doesn’t buy things like clothes very often. I have asked him a few times where he spends the money, because it seems high. I know the cost of living in London is high and I do not think he is splurging, but I do think he may be filing away the excess which is only a big deal because the money I send him otherwise would go to my retirement investment fund or to save for a house, which is a goal of mine that I had to put on hold.

He has stolen money from me in the past, so I may have some trust issues.

I have broached the subject a few times gently but he tends to shut down. I suggested we just put all his bills on my credit card so I know where the money goes but he doesn’t like that idea. I have also said we can sit down and build a budget but he just says “Just send me as much as you want to send me, and I will figure out the rest.”

Finally, I could not take my own doubts. I told him he needed to show me bank statements, utility bills, and his savings account. He says that it a major violation of trust and that I am implying he is wasting money. He says I am grossly underestimating the cost of living in London, and being irrational.

EDIT: We are BOTH Men; I am not a girl.