Friendship 'break up' advice

I've been friends with this person since we were 16 (now 27) and we were once incredibly close but over the years drifted apart and then reignited the friendship multiple times, mostly due to her not replying and also had a big fall out on holiday when we went travelling in our early 20s and things just haven't been the same since. I find being with her very intense and dread meeting up, which makes me feel so fake everytime. Despite trying to let the friendship just fade out over the last few years, she seems to end up back in touch, we meet up then she stops replying again and the cycle continues... We both ended up having babies a few months apart (she hadn't even told me she was with anyone!) but we found ourselves back in touch again and when my baby was born, she congratulated me, I thanked her and sent her a photo, which she ignored. When her baby was born, I congratulated her and was once again ignored. I decided at this point I was done and the friendship was over. We have mutual friends and recently met eachother at a friend's baby shower, I once again found myself uncomfortable and trying to be friendly so as not to be rude but distant at the same time. Since then, she's messaged to say how sweet my son was and that she's sorry for not replying and we should meet up. Ideally, I would just ignore her message (not like she hasn't done it to me before!!) But I feel like such a bitch and I know that we'll see eachother again soon at mutual friends birthdays/weddings/baby showers etc and I'm worried how it might turn out... Sorry for the rant needed to get this off my chest, I just want to end this friendship but don't know how! Any advice or shared experiences welcome! X