This is her problem. This is her insecurity and she doesn't have any right to tell you who you can or can't talk to, you know? However, I guess her feelings have to be considered, to be on the safe side. I guess all I would say is "I'm sorry that it upsets you, but there's nothing going on and I'm not going to delete her from my friends list simply because you have a problem with it, you need to deal with this for yourself". I mean, you can consider her feelings, but don't let her push you around.
To love is to suffer. To avoid suffering, one must not love; but then one suffers from not loving. Therefore, to love is to suffer, not to love is to suffer, to suffer is to suffer. To be happy is to love; to be happy then is to suffer, but suffering makes one unhappy; therefore to be unhappy one must love or love to suffer or suffer from too much happiness. I hope you're getting this down.