Still Me by Jojo Moyes

Lou Clark arrives in New York ready to start a new life, confident that she can embrace this new adventure and keep her relationship with Ambulance Sam alive across several thousand miles. She is hurled into the world of the super-rich Gopniks: Leonard and his much younger second wife, Agnes, and a never-ending array of household staff and hangers-on. Lou is determined to get the most out of the experience and throws herself into her job and New York life within this privileged world. Before she knows what’s happening, Lou is mixing in New York high society, where she meets Joshua Ryan, a man who brings with him a whisper of her past.