Beginner Gardening: please help ..my good looking Monstera is slowly dying, 2 by sannes

sannes wrote:
Hi all,
I am so happy to find this forum, there are many out there but this one inspires me at the most.
 I come from sweden and I got since many years  a Monstera Deliciosa and about 2 meter high and 1 and half meter wide, almost 12 years old.
I have never changed my routines with watering etc..and all was well until one  month ago the monstera started to get yellow parts of the leaves extremity and the the leaves one after the other tends to wrap himself, in other words  they refold itself, the extremities of the leaves are getting more like curly than straight,  gosh I cannot find the right word for this, but its more like the leaves becomes waves.  Please see photo attached.
It looks like she is slowly dying in front of me, and that she got too much or too little water I cannot imagen, since I have this plans for more then 12 years.

Please please can somebody help me, or did somebody experience this phenomen. 

Thank sin advance
Sus