Long time no see, fellow RPs.

I (29) have a problem with my girl (32). Let me explain (tl;dr at bottom):

About 14 Months ago I promoted one of my plates to girlfriend status. Everything went smooth and our social circles as well as families accepted the other relatively fast. She fulfilled a more traditional role, taking care of cooking, cleaning and stuff like that. She was very submissive and would want to cuddle and bang a lot.

As usual, sex got less frequent (3-5× per week) but still was pretty good and fulfilling for both of us maybe not so my neighbors.

Fast forward to about the beginning of the year. Had a great time together and she started her retraining in a boarding school. Every day she would call me at least twice and visit my place for the weekends. She being a relentlessly honest soon-to-be-wife, told me about a guy there she thinks is very sympathetic and she would want to befriend him. Of course, I saw no Problem by this at first. After she told me, he'd make sexually harassing comments and hits on her like no tomorrow, I told her that I'd dislike them getting closer and she froze contact to him. Everything went okay for both of us. Without my guidance she was unable to structure most of her free time there and grew depressed. Even more so, as her beloved grandmother, who played the role of her alcoholic and to no extent mature mother, to her passed away. 

Being physically absent, I tried my best to give support. Worked okayish, as she's a little stubborn. 

Fast forward again to about 6 weeks ago:

Our relationship still was good at that point and we finally discussed the frame of her moving in at my place and both of us living together. Man, was I happy.  But the following week, the guy from January talked her up and broke her defence like "I have a girlfriend myself, I ain't a threat." O told her I still disliked it, maybe because O just knew she cheated her ex a long time ago. They befriended each other and she started to smoke weed again. I don't think a joint some days ain't that bad and me not being a tyrant, I agreed with 'weed once in a while'.

To my shock, not only has this become weed Monday to Friday 4 to 3, but she's also everytime in his room with a buddy of his, at least she said so and I believe her. This brought upon me a shift in her mood pattern. Now she was hyped and euphoric on weekdays and just a shade of herself on the weekends. I watched this for two weeks and decided to have a serious talk with her, about how this isn't good for the relationship.

Hell broke lose. She stated that those guys told her things like she'd only be in a relationship because she couldn't be alone, she would have more fun in life being single and all such crap. She bought into it, telling me life was way more chill with those dudes and being with me was killing her vibe and making her sad because I wouldn't let her dwell on her bad mood. What the?

As we talked more and more and I grew a bit angry on both of these guys obviously hitting on her, she told me her ego needs this, because I wouldn't take her for an adult but a child? I would be clingy and oppressing? Okay, her feelings, so we change things up.

Now she only texted me the whole day and called me, after she came from the 'chill out sessions' at mostly 9 to 10 PM. Shitty situation, but okayish, as she has her own life and can do pretty much as she pleases.

Next weekend was horrible. As we smoked weed together (as I know it makes talkative in the right situation), she again stirred the oppression bullshit up, but told me, that she is annoyed of me at one point of the day, but misses me pretty soon after she told me to 'let's keep communication loose for the day'. Felt good, but was followed by it would sometimes be so extreme and hard for her, that she snuggled up with that one particular guy. 

My anger to this baffled her. 'He didn't even reciprocate it.', she tried to soothe me. What should I say, it hurt a metric fuck ton, that she started this encounter. In the heat of the moment I said that I'd punch this guy's throat and that I don't want her to meet up with him ever again. Which made her angry. 'He is the only one who understands me! I can be myself with these guys! You can't control me like that!'. Weekend was done.

The next week started pretty much the same as the others. Well, I was devastated and confused, but I didn't want to let her know. I tried to explain to her, how those guys try to manipulate her. She refused to hear my concerns and told me to stfu and let her make her own decisions and experiences. That those guys weren't bad guys. I hit rock bottom. I phoned her best friend and asked her for her perspective, to only realise I ratted my girlfriend out to her, as they hadn't talked for weeks. I explained everything above to her, asked her if she sees things the same way and my girlfriend is getting manipulated.

This weekend her 3 week holiday started. Initially we had planned to go on a trip together, but she called me on Thursday, that she has to sort out her mind and heart and therefore heads to her place for a few days. Let her do what she needs, I thought.

Friday she called me up and we had a nice little talk about how she feels a bit better. Saturday she called again and asked for me to visit her. We decided that I'd do what I had planned for the day and afterwards go to her place. The evening was beautiful.

We cuddled and had a talk about what happened and that she thought now this guy is an asshole and not worth anything as even as a friend he has to hide having contact with her from his girlfriend.

Sure, I tried to persuade her. But I failed. No big deal. During conversation she tried to calm me down by telling me she already made a pro-contra-list for both of us guys, to get into her head that this crush is bullshit. It felt like getting hit right in the nuts. As her phone rang, she read to me the message she sent him and his reply as follows: 'We can only be friends if I can be sure you aren't having any intentions. I have to get rid of this crush on you' - 'I can tell you to 99,8% that there won't be anything between us.' To which I thoughtlessly commented 'You wish she was that dumb, fuckface.' She started an argument. I was way too jealous and she would like to keep him as a friend again. She grabbed a book and went off for bed, after a good night's kiss. Letting me sit there like a fool.

The next morning, she was distant. She didn't touch me in the slightest, even preventing it from accidentally happening.

After breakfast she asked me to leave, as she needed time for herself. No problem, as I had plans for the evening anyways.

On the way home I got a message from her, stating that she's annoyed by my presence and that I tried to initiate sex all the time. Also that she was confused and didn't feel anything for anyone and is just sad. Being mild and understanding the last weeks and simply not able to hold it anymore, I accused her of being blind and having found a guy that's exactly such a manipulating joke of a man like her father and that I have to suppose it is this making him attractive to her.

Shit broke loose, we had a pretty bad message fight and phoned in the evening. I really grow tired of repeating stuff as mentioned above, but we basically didn't find a conclusion as she said she'd not be ready yet to decide anything and she just wishes to die. We ended the call agreeing to not contact each other for a few days.

Monday I got a message from her best friend, that she ratted me out. I was totally prepared that we were done now and she would cut ties. She called me the evening, going ape shot about me telling her best friend about her drug abuse, how she can't handle it anymore that basically everyone is pushing on her to stop smoking weed excessively. But that it was a huge hit to her trust that I did so. She even insinuated I wanted to get her manipulated by influencing her friend. It took a long talk to make her realise that I did not intend to brainwash people, but to save herself from herself. We agreed again on not reaching out for each other for a few days. Some messages were exchanged after the call and we promised each other to not give up without having tried to solve our issues.

No input from her since then. I checked for the 'last seen' randomly when messaging my friends. Seems like she was up to 6 am today and slept till noon. I'm worried.

TL;DR:

Girlfriend is physically absent 5 days a week for boarding school. There is a guy she crushed on. She started smoking weed with him and a friend after getting depressed as her grandmother (mother figure) passed away. They cuddled, at least she says so. I asked her to cut him off, she refused. Said she knows best is to keep me, but he was sucha good friend (he played soulmate card) and she needs time, as she feels nothingfor anybody atm.

The other guy:

Beta wimp that let's his girlfriend decide that he shouldn't have contact to his kids, as she dislikes women he had sex with. Complains about being horny all the time, because she won't let him smash. Has Quasimodo-posture and needs to keep his current girl for not being homeless. Has to hide basically every human contact from his girl, fearing she could get angry.

What should I do to save this? Is it even possible to save? What are the chances?

What were my faults apart from the obvious? Should I tell his girl? Should I call the cops and get them busted to protect her? Should I punch his face and fuck him up? I don't know any more.