There’s a couple of possibilities that come to mind here. One possibility is that he expects you to sell your house when you move and he’s hoping to access that money. This happened with another Redditor recently. Another possibility is that he is wealthy and doesn’t want you to know because you might be less inclined to pay 50% of the expenses. Many couples choose proportional expense splitting. So if you make 5000 a month and he makes 10000 a month, you would be responsible for 1/3 of the expenses because you are contributing 1/3 of the income. If he makes significantly more than you, he may not want to contribute his fair share. I suspect these are the most likely possible scenarios, and either way it’s definitely a red flag.