How things can go wrong :(

By searching for this pic (oh I love that) I stumbled across another which shows me and my "ex"-girl friend - if I can say something in that way and honestly I am not "done" with that theme because every now and then think of her.
We have been closest friends for more than 13 yeears here in Munich. You all know the older you are the less easy is it to make friends. So I was very very happy to find a girlfriend and soulmate and we solved every problem together - heartsickness and whatever... Every day we called each other - sometimes we spent the weekends together - every year we spend a few days together on holidays.  But I found out that it's mostly the same: When a man "enters" your life your life and your time changes. But when Achim "entered" my life  we all three (Achim, my friend and me) could handle that great. I told Achim that I need my time with my friend and the other way round. So no problem at all....
A few years ago I felt that something changed with my friend - asked her if something is wrong with our "relationship" or if I did something bad/wrong to her. But her answer was: No, everything is okay... But I felt something between us - it wasn't the same. I tried to find it out - couldn't find any sign.. Then she didn't call back, didn't answered my emails and "closed her door".
I know her very very good and I saw this behavior with other of her "friends" a few times and never thought that she could do something like that to me. But I was wrong. In our friendship she every now and then was a little different and it was always me who asked if something is wrong or if I did something wrong. But the last time I thought: No, why always me? Why do I have to solve the problem again (when there is a problem)?. She never tried to ask me when there was something a litte "wrong" between us. So I decided not to ask for this time. And what shall I say? She also did nothing and that means - no more friendship for more than 3 years now. First time for me it was very sad - I missed her - it was like a relationship has ended. I shared so much with her - she shared so much with me and I missed her calls and emails..... with the time it went better but honestly sometimes I miss her bitterly. So often I thought about sending her an email or a SMS or call her on the phone and then - why me again?
So sometimes I ask myself what can I do? Hub said so often that he saw it was always me who worked for that relationship and he thinks for her its not important enough to fight for this friendship. Maybe he is right. So sad that there is a broken friendship withouth knowing the reasons....