You can tell your girlfriend your bank card password directly. Since you chose to stay with her and live with her, I believe you must believe that your girlfriend is human, and she is not the kind of person who is insatiable. Here are two suggestions.

First of all. Since you choose to be together, you can tell your girlfriend your bank card password, which will make her feel that you trust her and that you are getting married. If you don't even tell her the bank card password, she will think that your love for her is not whole-hearted, which will only make her feel insecure.

Second. If you don't trust your girlfriend, you don't have to tell him. You can tell him when you get married, and then all the wages after marriage will be in her charge. I'm sure your girlfriend can understand.

Finally. When two people walk together, they will eventually involve privacy issues such as their salary and income. I think if you love your other half, you should have no reservations about him. It not only made him feel at ease, but also made him have no choice, thus strengthening his choice.