It is more likely that the savings card you said should be a debit card, which doesn't matter.

If it is a credit card, that is, the credit card we are talking about, you must use my signature, which seems to be more troublesome, because when we go to the supermarket to check out, they will emphasize whether I spent it or not, otherwise we can't use it.

Don't worry if the salesman doesn't say anything. At most, I'll let you copy your and your boyfriend's ID cards to prove that I agree to spend.