What should I think? Relationship advice, please?

My fiance and I have been in a rough patch. We've gone through a lot, from her family ditching her when she was homeless, and me taking her into my families home, and then me getting us our own place together, paying for everything until I made a mistake when I was incredibly sick and losing my job because of it. This is where her sister ended up disliking me, because the way we were going to pay rent is I had two thirds of it, already. She was supposed to give me the last of it, but instead got a piercing and said, 'We'll work it out'. And presented it all as if it were my fault to her family, and nobody is letting me tell the real story here. I'm currently in school, to get us further in our futures, and looking for a job. But she left me last night. Called her mom to help her get her stuff out. I told her she'd regret it. Said I didn't want her to leave. Begged her to stay. Smoked a cigarette while her mom showed up, and then she blew up. She freaked out at me, and I mentioned that she's the one who hits, she's the one who blows up and sabotages the **** out of everything, and she's the one who came home with chlamydia and shared it with me. (She didn't cheat, this was early in our relationship, and honestly no big deal to me, other than I had to get treated, and I felt sickened by for awhile.) I said it out of retaliation to being told to **** off, and all sorts of hurtful things, I didn't tell her she had to leave, I just wanted a second chance cause I gave her a dozen. Her mom's hated me for awhile. When she wouldn't give me that, I told her she'd end up regretting it, and that I wanted her half of everything I paid for. Again, out of hurt, resentment, anger. But what I don't get is how, when she was facing homelessness, they all told her she did it to herself. That she had to fix it alone. She slept in a car outside my parent's house until I convinced them to let her stay with me, until we got our own place. I don't really know what to do, or what really caused this. I think it was her family wearing down on her for the three days she spent with them, and my stupid question if she was really staying with her family, or this guy she used to **** around with while she was with her last boyfriend. Two hours after she left, she came back. A mutual friend who I introduced her to gave her a ride over, (the mutual friend is living with me now, kinda((She doesn't stay most nights, but with her new bf)) She begged me to stay with her, to forgive her. Hurt, I told her that she did this to us. That I had no part in making all of this **** happen. That when I asked her for a second chance, she said no, but then reconsidered after all went down, telling me she "wanted a relationship with me" after all her stuff was in her mom's car and we took a second alone to say goodbye. But she came back, begged for me back, ended up lying to her sister and staying the night with me. Promised me to stay another night, but we were gonna do this staying at different places for a bit. Cause that's what she asked for, and I asked for 60 days to get everything together, and do that on my part. She said okay, then all this whole shitstorm went down.