I think that when there begins to be regular amounts of conflict and drama in friendships, you need to cut them loose. It has taken me a long time to come to that mindset. I used to be the opposite. I would cling to friendships, my friends were like family to me and I held this unrealistic belief that most of them would go on forever. I held friendship to be almost sacred, and for that reason, I wouldn't give up on a friend just because we were going through some growing pains, or having conflict, or they were having problems.
I still value my friends highly but I also no longer have the space in my life emotionally or the time for drama. Plus I had to realize later in life than most that the majority of folks did not view friendships with the same regard as I did, and as result I tended to get used, or hurt, or was left feeling taken for granted way too often. Leads to a lot of resentment, which I loved to blame others for, but ...hey. I was foolish. The majority of my best friends that I had known the longest have all exited my life in the past few years, starting around the time that I met my husband and had a child. The ones I remain close to live far away.
For me it has been one of the hardest parts of becoming a mom, and I'm still mourning the loss of my social life and having a group of girlfriends that I really loved. But I know in my heart it happened for a reason, and I will eventually make new, better friends. I may have even started doing that, but we'll see. Bitter experience has taught me to be skeptical. Sorry, I'm getting morose and kind of went off on a tangent :)
To answer your question, yes I do still miss some of my former friends a great deal and think of them often. Mostly, I wonder how they are doing and hope they are doing well. There is like a loving curiosity always there. In some cases, it is still painful even years later. However, there is no regret on my part for making the decision to end these friendships and in the one instance where my former friend ditched me, I think she did me a favor. I think whenever you get that feeling of dread over talking to your friend, or seeing her is always stressful, then you know distance is certainly needed. I like your idea of starting to create a boundary and then you can decide once you've had some space if it feels right. There doesn't need to be a big confrontation or "talk," as much as we fantasize about this kind of closure, it can wind up being hurtful and critical. Sometimes it is better for years to go by before having that kind of talk, or not at all. Unless you both happen to be exceptionally mature, communicative, open self-reflective people. Let's face it, most of us are not quite there (but we try!)
I wish you luck.