Absolutely would and I have done this. I have given her a credit card and they have gone on a shopping trip. The first time she did this, it drove me absolutely crazy for several reasons. First, it was totally up to him how much of my money he was going to spend, which caused me both anxiety and excitement. Second, they had a fantastic time together without having to worry about how they were going to pay for it.
It was also very hot that she did not give him any boundaries on how much of my money he was going to spend on them and she did not second guess him.
Now all of this said, it would not have been so hot if I did not have the money to pay for it. I make good money and that was not the issue, it was just the thought of her lover spending my money that was very hot!!
Let me tell you, they fucked like crazy after that shopping!! I loved it all too, because it totally blew my mind thinking about the reality of it.