My partner can't make up her mind

So to tell you a little back history...

I've been married to my partner for almost 6 years. She been through a lot of trauma in her life and so have I. At first everything was great and it seems like two lost souls found soulic in each other. We where both kicked out of our parents home shortly after we started hanging out together. The first 2 years where tuff but we struggled together and made it. Then shortly after she got pregnant and to me it felt as though she was pulling away. I even found out later from her sister that she wanted to abandon me and my 2 daughters from a previous relationship and move out of our home into low income housing. After talking to her about it she denied it at first but then she came out and admitted the truth. Then when covid started things kinda got really bad between us. Stress and frustration took its toll and we took alot of our stress and frustration out on one another pretty much like an eye for and eye so to speak. And the last 2 years have literally been like hell. I said alot of nasty things to her and also decided to stop even sleeping in our room to avoid her and eventually just kinda shut down entirely and she basically did the same thing back. Alot of times talking just lead to fights or one just putting the other down.

Now let's lead to my current situation. With everything we did to each other I found out that she wanted to finally end things and started filling out paperwork for the divorce after we talk about just separating for a bit. And I don't blame her for that especially after the things I've said to her. But we talked about saving our marriage and then out of the blue on my daughters birthday I found the papers left out. When I brought it up to her she basically told me that she love and cares for me but she has fallen out of love with me at the beginning of the year and she's just been faking it this whole time. As of our agreement we would live together after I started my new job until I can catch up on my back debt caused from losing hours from my last job when it changed owners. But recently I found out that she's been messaging someone else. I know I shouldn't have done so but in the morning I shut her phone off because she falls asleep watching Netflix. I saw the messages between her and the other person and I instantly felt heartbreak seeing that the guys name went from being frank to "sweet heart Italian" in her phone and she also changed the background theme to love with hearts all in his name. While scrolling I saw them saying I miss you and that they where calling each other pet names just alot of things you don't normally do if they are "just friends". When I asked her about it and brought it up to her she played it off saying that she not that type of person to just go around and start cheating when she in a relationship because it's happened to her. But at the same time she still hasn't given me an awnser on if she was going to proceed with the divorce at the end of the year or wait.

I have been going through therapy because of everything that been going on. And my therapist has diagnosed me with borderline personality disorder. And that was one of the things that me and my partner agreed on before we started marriage counseling. I've been continuing it and made some progress in my session. And now lately me and my partner have been talking and opening up more to each other. It seems like one day things are acting like there's a mountain between us and then there's other days when I'm helping her out or getting things for her she seems to act like she wants me around and that she really cares about me again. The last time we talked the admitted that Frank was her friend and because of things going on between me and her and our issues she started confided in him and they became closer to where she likes him but she feels as though it the hero complex where she just likes him because he was there for her. But I'm still not so sure. And with things with us seeming like they are getting better and that we have been kinda doing things again like couples do I'm just so confused and mixed up. I feel betrayed in more ways then one, but I want to fight to stay with the woman I love and want to be with.

Sorry it was so long. But I just need some outsiders perspective.