There's an air of tension because your relationship has changed and it's difficult to switch so easily like that. I am friends with one of my ex's and I found that we had to have some time apart from each other first. Then broken hearts can heal etc. It was then possible to come back together and be friends in the true sense of the word. We talk about each other's partners now and everything is fine, there's nothing in it and nobody is getting hurt. My suggestion to you is that if you really want to be friends, I would find out why first. Was she really that good a friend? or can't you bear not to be in her life at all? You need to think with your head, not your heart and be strict with yourself. What can being her friend possibly give you? Anything positive? If you have other friends you can perhaps do without her. The ex that I am friends with, I was never in love with, so it was easy for me to switch. A different matter though for him. We had parted and then became friends a couple of years later. However, if I was in love with him, I would never have thought of wanting to be his friend, because like I said, I've done it before and nothing good comes from it. All that happens is that it takes longer for you to get over them. The feelings of love linger because you are still spending time with them, still seeing what you always loved about them, still laughing and having good times, and perhaps mis-reading simple signs as evidence that they are still in love with you too. You end up waiting for them to say they made a mistake in leaving you, and how they love you and want you back. In my situation, I ended up waiting for three years before I realised that he was defitnately not coming back. I'm not saying she won't come back, she very well may, but it has to be off her own back, no coaxing from you. You can't live your life on she may do this, or she may do that. You have to accept it's over and she doesn't love you anymore because this is what her actions are telling you. I wouldn't see her anymore if I were you. It gets in the way of you moving on.
My advice? I would do what my sister always calls 'blowing them out'. Which is basically, don't say anything to her about it, just allow yourself to drift away. See less and less of her until you don't see her at all. She doesn't love you if she broke up with you, so you need to think of yourself and look after your own heart, because she is looking after hers. Do what's right for you in order for you to get over her as quickly as possible, because a broken heart is no fun. In these occasions, your head must rule your heart in order to look after yourself.
I'm sorry! I really feel for you as I'm nursing a broken heart myself, but it's on the mend!