How do you stay friends with your ex who broke your trust?

For further context I met a girl who was friends with a couple of other people in my friend group about 8 or 9 months ago, and we had gotten along well. After a while she eventually admitted that she had feelings for me and we started dating. A couple months into the relationship she had moved in with me and things were going great until about halfway through the 2nd month of her living here when she said that she felt like she had a crush on a friend of ours.

At that point she asked if we could have a serious conversation and she went on to express that she was having conflicting emotions, and that she wasn't sure on how she felt with the relationship. After a few hours of discussion we agreed that we both needed to be more open about her emotions and work on the relationship together.

However over the following 3.5 months until the breakup she would never actually express how she felt, and would consistently prioritize her friends (including the one she has a crush on) over me both in time allocation as well as expressing herself emotionally (for example our friend who she had a crush on as well as said friends boyfriend and two other friends of hers knew about that crush weeks before I did), and even though I stuck to my word and started to open up more about my problems with the relationship I would always get brushed off or she would start crying and make me feel like a jerk for bringing it up while admitting that she was wrong for doing it.

So after that time period she eventually said she wanted to have a talk again and that she was unhappy in the relationship, initially she wanted to take a step back or a break from the relationship, then she said that she wanted to just break up, then eventually after a few more hours of us talking about it we both agreed that we would take the time to fry to work it out and see if the relationship could work. Then the following evening at midnight she started crying and told me she couldn't do it and that she wanted to end the relationship.

My struggle comes from the fact that we still want to be friends and we are still living together in a one-bedroom apartment.

However she also admits that a lot of the problems were her fault but she refuses to acknowledge that she has to put in the work to change that for herself, and keeps repeating the same behaviors. Because of this all of my trust for her has been destroyed because for the past 7 months she couldn't even be honest with me as her boyfriend about her emotions, nor could she communicate about where she was going to be or even just keep a time frame that we had set up for us together without bailing for her friends instead of me, nor could she even treat me as an equal priority while we were together. The final straw for my trust being broken was after we broke up she even admitted that for the first four or five months she was extremely self-conscious and just latched on to the feeling of somebody liking her which made me feel extremely used and when I tried to express that she then told me that "it's not like that it's different". Then there's the fact that she is still not accepting the new boundaries of us not being in a relationship and me not providing for her like I would when we were together. Such as her having to pay an actual 50/50 split of the bills and not me paying most of them.

At this point I am aware that I'm her last choice and always have been it seems, and that she is not going to be willing to change because even through the 7 month relationship when I expressed how I felt about any of these situations she would just either get defensive or brush me off. At this point I'm not trying to salvage the relationship, I just want to find a way for me to heal from the breakup and be able to move on as friends.

TLDR; my girlfriend left me because she felt unhappy in the relationship, however throughout the relationship she would refuse to express her emotions to me or open up to me in any capacity about her feelings and the relationship, and would constantly prioritize other people over me, both in the capacity of them hearing her emotions before me as well as prioritizing time with them over me. Now I am just trying to find a way to heal and move on without harming our ability to be friends even though I am lacking any trust in her after the past 7 months of constant lies while we were together and showing zero signs of improvement after the breakup.