Simply Google in the search bar: Why Kurt and Goldie never married
The answer is there.
Goldie explained that both have been in previous marriages that ended in ugly divorces. She likes maintaining her independence and having the freedom to make her own decisions.
Yep, just like I said about making unilateral decisions without guilt.
This type of relationship dynamic is all about convenience. You can still get the companionship and the support while maintaining total independence. You are not fully committed, only committed enough. You no longer have expectations and worry that whatever the other person does will impact your happiness. It works more like a friends with benefits situationship but at a more mature level. If you're lucky to find someone who isn't a complete jerk, it might actually be a very good thing for you. The problem is that most people don't get a good, secure person, because good, secure person don't tend to go for this.
I'm not knocking it down as some attachment style will only work in this dynamic. I'm just saying that most couples in this arrangement end up feeling completely used, abused, deceived, and their time wasted. The breakup is not as easy come, easy go as it claims to be.