There is no such thing as a perfect relationship.
Each of us is different, therefore each relationship is different, moreover each of YOUR relationships will be different, because it is formed of two unique different people.
To make matters even more exciting, also your stable relationship can become different in time.
Since a relationship is formed of two distinct people, it's enough for one of them to change, and this will change the nature of the relationship.
This brings us to a conclusion, even if a perfect relationship existed, it would still be subject to various influences from both components forming it.
It would be enough for one of the partners to change and the relationship would change.
This leads us to even more interesting thoughts.
When we see a couple and think, "oh what a perfect relationship they are forming", it is only in that moment that the relationship is subjectively perfect.
One moment later it might not be so perfect any longer.
This should inspire us to be really living in the moment.
Let me explain.
If things are going great we need to be truly grateful for this as the status might shortly change.
Conversely, if things are not going so well, we should not worry so much, as the only constant in today's world is change.
There is more to this philosophy however.
It is the Law of Attraction.
Wholesome thoughts we form in our heads, lead us to being a wholesome person and in turn attract wholesome relationships.
What we think impacts who we are, what and who we attract to our lives.
In fact what we think forms everything in our lives, including the type and quality of our relationship.