Again I’m not the best to take advice from but what I would do in this situation is say ‘L, I feel like you just cannot keep up with the outside session contact that you promise.. The fact that you encourage me to ask for it and then aren’t able to provide it is really confusing and hurting me and I can’t do this anymore. I want the support but can’t handle the pain of you not doing what you say you will. I need some clear boundaries. What outside session contact can you offer me that you can be consistent with?’

I feel this will communicate to her how much her poor boundaries are hurting you & help you feel in control of this crappy situation and not like things are being taken away if she does it

No, should not have to do this but if you want to try and make this work again and feel like an adult in control then this is how I would play it