Now, though, she is asking him to do things one on one. I feel bad because she is very nice but I feel that there is a difference between being friends in the sense that they can get along, share the same friends, be on good terms, friendly whatever and being friends in the fact that she is initiating one on one hang outs between them. I told my boyfriend that I was uncomfortable with this and while I am glad they are friends I think there is a fine line to cross.
When you told your bf all that did he agree to not engagiing in one-on-one date-like activities with her? Did he agree to only be friendly and friends as far as group only activities go? No private chats on the phone, emails etc?
Please note that I am not worried about my boyfriends cheating--he would never and completely understands how I feel.
Yes you are worried or else you'd be fine with one on one activities. And, yes you are concerned he will cheat maybe not physically but certainly emotionally, (which often leads to the physical if the emotional continues to be fed).
As for your question: MOST people would not be okay with their bf or gf hanging out one on one with a past lover who obviously still wants their partner. If your bf had half a brain he would have not given her mixed signals and he would have left her alone with zero contact so that she could heal and get over him. My suggestion is that he back off and distance himself, refuse to meet up with her or initiate any email, phone, text, snail mail or notes via carrier pidgeon so that she can get totally over him, get on with her own life and find her own one-on-one date to do activities with. He's stagnating her progress and he's causing a problem in your relationship by continuing on with her.
Try to stop feeling guilty for pointing out that your bf is crossing a very fundamental relationship boundary by doing one-on-one activities with this woman.
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion