until yesterday I had a good friend. We might have not talked very often, but we kept being very good friends anyway. I care about him a lot. We know each other for 6 years now, we've been through stuff together, some real, some fictional and some in-character.

We also dated for over a year. We broke up on good terms, got over it and kept being good friend.
Oh, and yes, I do love him - just not in anyway romantic. Love comes in many kinds,not all romantic, and I love him dearly.

Now,we stopped dating 2 years ago. Now he has a new girlfriend. I knew she had a bit of a problem with me, but he kept telling me that he explained to her that we are only friends and that she shouldn't worry, turns out it didn't work.

Few days ago she broke up with him. He contacted me and told me that we wont be talking anymore and not to call him. I tried to ask why... though I knew, and eventually he answered the phone and told me what happened - and I was the one who made sure he is okay and asked to help him and made sure he won't be all alone (and no romantic thing happened,at all. we just don't feel like that about each other.)

Yesterday he called me to say the same thing again,he was cold and didn't even want to hear me out. I told him that I care about him, that he should be careful not to let her hurt him, that if she was the guy and he was a girl people would have looked at that very differently, that if that's his choice then I hope he's happy with her and that I'm anyway always here for him.

don't know what to do with myself.

In my opinion, theres nothing to do. No matter how stupid the decision is, its still his to make. It sounds as if youre a good friend just trying to look out for him but hes just not listening. The only thing you can do now is go about your life and hope she wont hurt him. If she does, just provide comfort to him. No matter how tempting it is, do not say I told you so. lolz
Being honest, she sounds as if shes threatened by you or shes insecure about their relationship. (not to mention that cutting him off from his friend was a bitch move) Dont let it bother you much. Atleast that's my advice.

I can honestly say that if she sees a problem with him talking to you that you should let it be. I understand that it is very hard, but I've been there before. I know what it's like to look at someone and not want them near my boyfriend. It is not because of an insecurity. I promise you, she feels like she has a good reason. And frankly, it would make THEIR relationship hard if he were to go against her will. If they break up, then that will all be fine. But for now, it is between them. He should respect her.
If he has a counter argument for her and asks her why she wants this and such, then she should listen. But all the same, this could very well have happened and this is the decision that is staying.
I'm sorry, I know it is really hard. But If this is what he chooses, then please don't make things worse for everyone.

*** It CAN be because of an insecurity, but in my situation it was not. You never know what it may have been.

>>2 I Agree
You can't do anything about that situation but let him go on with his choice. If things doesn't work out he'll realize that he left a good friend behind. You just comfort him when that day comes. If you want, you can check up on him again b/c you care. He can't say anything to your decision to do so, because he made one himself and just needs to respect that you just wanted to make sure he's living happy.