Hi and welcome Processing,
you got a point. Most people on this board I hope would agree that there are positive sides to their partners.
It is normal that there is a big relief with some sort of formal or best guess by member diagnosis. Your life over the past years has become increasingly bizarre an having a name to put on it and knowing you are not alone is helpful. You find much on that in
LESSON 1. But it won't change much and focusing on diagnosis and labels won't change a thing for the better.
The following LESSONS for that reason focus on changing our behavior as that has immediate impact. It starts in
LESSON 2 among other things with radical acceptance. Which is in some sense what you are saying - wife likely had BPD, that fact I acknowledge - let's "think about other things?". It then continues with skills.
Now when it comes to "think positive" we got to be very, very careful. There is a lot of negative in our relationship and more often than not the worlds grey is perceived as pitch black by our partner with BPD. Think positive - if it works for you - is fine. Think positive messages in moments where our partner is thinking black are invalidating and are increasing emotional regulation problems in the shore and long run. BPD is a condition very strongly related to invalidation and we have to be super careful that our positive thinking and intentions are not doing damage. Learning to not send positive vibes in the wrong moments is one of the easiest things to learn that has a real impact - we stop making it worse. Validating negative thinking and negative emotions is then helping our partner to calm and us to understand them better.
We are also receiving a lot of negative messages at times. Think positive is not enough - we are stonewalling the sender and more mud gets hurled into our direction. When the mud rains it is hard to ignore and our brain is torn apart with attention spent on ignoring the negative (and do what with it?) and maintaining positive thinking. What works is validating the negative and thus reflecting it away from us - yeah it is black but it is also not us. Think positive but spell out the negative that comes our way.