Sophia Winston is the only character who could arguably be seen as a love interest in the story, although the Jinni loves her as much as the Golem loves Michael—in other words, not much.
It's a shame, because she and the Jinni complement each other very well. Early on, we learn that Sophia, despite being from a wealthy family, isn't one for the society life: She says, "I can't stand these parties, they're so wearisome" (7.83). That's something both she and the Jinni have in common: absolutely no desire to socialize. Sophia also wants to see the world, and like a famous movie involving a jinni of a sort, the Jinni can show her.
But all he actually shows her are two nights of hot lovin', and then he ditches her. With a jinni bun in her human oven. She miscarries and gets very sick, and while she's angry at the Jinni, she also shoulders some of the blame: "She wished she could blame the man who'd come to her balcony, but she couldn't, not in fairness. He hadn't forced her, had never so much as pressured her" (20.88). Add willing to take responsibility for her actions to Sophia's list of good qualities.
In the end, she helps the Jinni recover after he tries to commit suicide by fountain. She also calls her engagement off, and hopes to travel to some warmer climates. Perhaps she and the Jinni can rekindle their love.