> Why would you need or even want to be independent?

Because I would want my kids to be able to get out of an abusive partnership if they needed to. See the history of domestic abuse.

> Why would you plan to form a family while keeping your options open/having one foot out the door?

Everyone should have options open for basic sustenance. Death, abuse, job b loss, etc. As they say in engineering, two is one and one is none.