How do these differences create tension in their relationship?

Grant's beautiful mulatto girlfriend, Vivian, lives in Bayonne. Like Grant, she has a college degree and works as a schoolteacher. But while Grant is often frustrated by his job, Vivian loves working with the children and is kind and encouraging to them. Grant takes Vivian for granted. He expects her to be there for him both emotionally and sexually yet he seldom reciprocates with her needs.