“I remembered for the first time since I hated you that I used to love you,” she sang. Gwen Stefani debuted her new song that she says will probably be the first single of her next album. In an emotional performance, she sang “Used to Love You,” at the MasterCard Priceless Surprises concert in New York Saturday. It’s been about two months since she filed for divorce from Gavin Rossdale. They were married for 13 years. MORE