"I don't know how and where to start with this... I'm alone, miserable and I am seriously at the end of my rope. Sorry for the long wall of text-I really need advice and I don't really have anyone to lean on.

Okay,so this is how the events unfolded. On sunday, I was at her place. I had to check my e-mail, so I used her laptop. I opened gmail, her account was already signed-in. As I was about to log out, I see a hangouts notification from one of my students (I am an assistant professor at the local university ). Out of curiosity, I check what it was, and find out that they were sexting. Not only sexting each other, but berating me too. They had fixed a date the next day, by 7 pm at a park which is a few hours away from where we live. I smashed the laptop shut and stormed out. I think she probably figured I knew something, because I kept getting paranoid texts from her the whole day. When I got home I realized how foolish it was of me to not collect any evidence. I was only going to regret it even more.

So, the next day I drove to the park by 7. Part of me wished none of this to be true. But when I got there, I saw her car(which is mine) parked there. I walked by the car, and my gf and the student were making out. I knocked on the window and promptly asked for my keys. They had that deer in headlights look, and I could literally see her face turning pale. I also told her that we were over and to never contact me again. She starts sobbing. When she asked me how she'll go home, I asked the kid to drop her home and he just bolted. Just ran for his life. He even left his phone in the car. I locked the car, and left her there and drove home. I guess I'm too petty to be the "bigger person" and drive her home.

She kept texting me the whole day, apologizing and asking for another chance. I blocked her and went on with my business. I was very rattled, but I could function. I didn't want to talk to anyone, atleast not then, apart from my best friend but he is away on his honeymoon so I didn't bother him. I had a few drinks and went to sleep. I woke up at midnight and went through my bank statements, and cancelled our joint account, from which she had withdrawn a large amount that evening. To clarify, she did have some money in it, but almost 80% of it was mine. So I texted her that I want my money back or else I'll press charges, and that was it.

My phone kept ringing that day so I turned it off while I was at work. She kept calling me from unknown numbers. When I got back home and turned my phone on, I had heaps and heaps of notifications. She posted on facebook that I had been cheating on her, and tagged me. She also added that I was emotionally abusive and a two faced douchebag. The post blew up-it got more than 300 likes, which is a feat for her.

We went to the same university and have a lot of mutual friends, and a majority of them blocked me on social media. Someone created a group on WhatsApp, where they were swearing and cursing at me and calling me a horrible human being. I was appalled, obviously. They were even posting memes about me. My younger sister called and yelled at me, called me a piece of shit. She told me that she is ashamed to call me her brother. She told me that I'm following my father's footsteps(he left our mother for a woman half his age. My mother got depressed and died a few years later. They never divorced). She refused to hear me out, and told me that she had heard enough from my ex. While I could handle losing a few acquaintances, my sister is the only family I have left. I don't know how to handle this...

The only person that has stuck through is my best friend and his wife. We are very good friends, and he does not believe that I'm capable of cheating, rightly so. Even when my family refused to believe me, he did. I'm thankful to have someone, at least. He has shortened his honeymoon and would be coming back this weekend.

I have ample evidence that she was cheating on me, from the texts that she sent me. I also have the kids phone, which is locked, but I can see notifications from the lockscreen. The WiFi to my place connected on his phone. Surprise, surprise. She had texted him some stuff about her wanting to leave me and marry him. I cannot fathom how she could have an affair with an 18 year old kid with the hygiene of a wild pig.

I don't know what to do with it though. Nobody is ready to listen, even my sister. She has stopped talking to me. She has blocked me everywhere.

How can I deal with this? I have worked very hard to build a reputation in my community, and she has ruined it. I have lost all goodwill among my peers and friends. Is there any way to convey that I am the victim, not her? How do I fix my relationship with my sister?

What the hell do I do?

Tl;dr gf(25F) cheated on me with a student of mine(18M). When I caught her and demanded all of my money back, she played the victim and turned my friends and family against me. Even my sister hates me now. How do I deal with this?

EDIT : Thank you people for hearing me out. I never thought that strangers could be so understanding... You people are real gems. Well, I was done with my sisters crap and went straight to her place and just put the evidence to her face. She has been apologizing profusely, and is making me stay at her place until all this resolves. She is an awesome cook, so I guess the 5 hour drive was worth it. Also, more stuff has happened and ex is in deep shit. I'll make an update post tomorrow. Right now I'm exhausted and I just want to sleep. Again, thank you guys."

/u/exgfisapos you have to wait a few days before you update the ridiculous story.