Not a single parent is perfect. Even if your father and mother would have been some kind of Buddhas, they wouldn’t have been ideal for you. Even Buddhas aren’t capable of giving a child what it needs, since the needs of a child are endless. Besides that, parents have their obligations and responsibilities towards their children. This means that they can’t just fulfil all their child’s needs. The result is that everyone of us has a jar of unfulfilled needs that has to be filled by something or someone else.
A couple relationship isn’t a relationship between two people, but a relationship between many people. Think of it as the congregation of two planets: each planet is connected to a bigger picture. As human beings, we’re also part of a bigger picture: a family, a living environment, a country, a culture. When you’re in a couple relationship, you will also deal with his or her family, living environment, culture, etc.