Book about a wealthy female cat burglar

I don't remember all details of this book but I remember there was a rich young lady who owns a company that makes security systems. She also steals from stuff like art work rich people and gives the money to charity. She went to streal from one house one night and gets caught by a guy who's a guest there. She convinces him to hold unto the painting to prove her point. It's a romance novel
I also remember in the Epilogue, they had to go to a costume party and she went as a cat burglar which made him angry. He made her stop the stealing earlier because he was convinced it was dangerous