I hate this feeling! I am going crazy?

Hi..I'm new to this, so forgive that I' all over

I don't know what to do in my relationship? I feel like I am the bad guy in everything right now,, and that pisses me off because I didn't and It's
I have never been in a better place in my life as I have been in the last year. I have always dealt with depression and self hatred, mostly stemming from my being gay in a highly religious family/community that told me I would go to hell for every mistake I made. I have dealt with a couple of suicide attempts. One was more of a reach for help, but something serious none the less. I was that person that just believed they were not worth being happy in their lives. But somehow, I've overcome that and feel like I have become a strong, formidable woman. But this situation I have going on with my partner right now has me feeling these old feelings that are eating away at me. Am I going crazy?

I came into my relationship with a new outlook, a new understanding of myself, and a new respect for my significant other. And it has been incredible for the most part. If you don't count any of the lies that my gf has told me. And that's just the ones I know about. It started off with stupid things that were so ridiculous to even have to lie about. I'd find out, confront her, she would promise never again. Then I found the conversations where she engaged in some sexually explicit conversations via text with a male friend of hers (while I was hospitalized for surgery). I found out, confronted her, another promise...There was an old friend that professed her love to my gf and would email her poems that she wrote, and they text and talked a bit. Still reeling from the last friend that she did something stupid with, I asked her to cool it with the contacts at least for a few months until I was able to better deal with it too. She agreed...and again, she lied....I find out that they had been regularly talking and texting for months and it was always when I wasn't around or at work or something. Hell, she called her a time or two when I hopped in the shower. Even when I had the proof in my had I asked her directly if she was talking to her...nope, not at all. That was all I got until I showed my cards. Then she eventually told me what i have to assume is everything, as well as a few other things that she had lied about that I didn't know yet. So it's becoming increasingly clear that she has a problem with lying. I want to work things out because I love her immensely. But I have to know when to say when right? Hell, am I even justified to be upset by all this. I feel like I was just kicked around by her over and over. I just don'[t know what to do...This is the first time in years that I have felt this upset about anything. I trusted her with every bit of my heart, and I just gave it to her. Then she stomped on it for a while before I was able to put those pieces back together.
What do I do? Should I trust her ever again? Am I doing the right thing by staying or is it just sending the messagge that it's ok to break my heart? I just want to disappear into nothing and just not feel anyjmore...Why do I feel like by staying? What can I tell her I need from her i order to heal? Is it ok for e to look at emails or texts for my peace of mind in the beginning? Please help me understand this, I am so alone rith now.
I feel so desperate and hopeless, and I don't know how to be any of that. I don't want to get to the point that I can't pull myself back up...ughhhhh.

I understand that you love her but I believe she has crossed the line of forgiveness. I would have already have to have left. I don't see that she is even trying to change and that is a big deal. I would cut my losses and get out. I don't see anyway this can get any better and it is undermining your mental health.

I'm sorry. It's just my opinion.

Thank you Gayle, sui much to figure out.