The strange thing about love and long term relationships is that most of us are totally unprepared for them.
Imagine if an employer gave you a set of tools or computer programme and just said, there you go, figure it all out yourself, for the rest of your career. If you make a balls up we'll get rid of you, make you feel worthless, and take half of your future earnings.
From school age we're taught the basics of all sorts of subjects that will help us in further education and hopefully in our careers and how we contribute to society in general. Some move on to further education, University and other variations. We start our first job and our employer gives us specific job training, we learn from other skilled / experienced workers, we finish our "apprenticeship" and become a skilled, knowledgeable valued and sought after member of the workforce and therefore contribute to the wider community.
One the other hand, you meet someone and start a relationship - you're on your own, you might just get some advice (usually poor) from your mates, or you've seen family and how they interact (often badly). When I got married, the priest asked to see us for a discussion on how to make our marriage work. It was a single one hour session, off you go, that's all you need to last you a lifetime. He spent more time discussing the parking arrangements.
Now you're in a relationship and it all goes wrong up, you try counselling. That's the employers equivalent of a disciplinary, you only get that when things have gone wrong, by then it's usually too late.
Basically the majority of couples are winging one of the most important areas of their lives. We shouldn't be surprised so many of our relationships end up with sackings.