How should I treat the two most important people in my life?

I'm having real problems with my girlfriend and my best friend. I'm 25 and have been going out with my girlfriend for the past 9 months and we get on.

There is a situation where my best friend has moved to Switzerland for a job but before this my girlfriend and him didn't see eye to eye. I think it was because before me my friend depended on me to go out and once I wasn't around when I met my girlfriend he turned weird. We are still friends now and we email each other and going out to see him for one weekend. However my girlfriend doesn't seem to like me doing this as she says we have a strange relation where we rely on each other for emotional support.

I know where she is coming from but I don't want to turn round to my best mate and say he needs to move on with his life as at the moment I think he is still living in the past. My girlfriend has made harsh comments about him when I mention his name which I have told her about but she has said she will make the effort to ..

.. go out for drinks with him when he is back for xmas. What should I do?

I dont think your girlfriend has a right to pick your friends, or tell you who you can spend time with. I think you need to take a stand or you will spend the rest of your life letting her tell you who you can be friends with. Maybe she is jealous or feels threatened by your relationship with him. Emotional support, and going places are things friends do. Nothing weird about it.