I think we have talked about this before. Yeah it's difficult.

I think we need to observe those who are successful and model our own behaviour after theirs.

There are reasons though other than our ability to maintain relationships. In my case I have moved a great deal. I just don't allow myself to get too close to people. Consequently it is acquaintanceships I build and rarely take those further. Based on childhood experience, trust is a big issue for me too.