Hey there,

pretty simple thing:
My GF and I recently moved in together about 3 months ago. We have been together since early 2021 and I thought this was going to be my wife. We had plans together, this and that.

Yesterday at a Halloween party she broke down to me telling me that she wasn't very happy in our relationship. We went home to discuss it and at first she said that she was not super happy with our new living arrangements and told me that she is unsatisfied with my cleanlieness.

At the party the sister of my childhood friend said that the first realtioship is usually something that is used to test and learn and is not meant to last. I am her first boyfriend and she repeated this statement while adding that she is scared about being with only one person her entire life.

After a while of talking it got clearer that its less about my cleanliness and more about that she has an interest in one of her classmates (school for work stuff). We had this issue before where she had a crush on my best friend, we worked through it and it was fine, this time however she said that he confessed that he has feelings for her too.

After another while of talking it got out that they were studying at our apartment on monday, where he tried to kiss her and she turned him down. On tuesday they met up again at our apartment and left shortly before i came home to go on a walk. They kissed then. That evening I expressed, that i thought that that was weird and made me feel not so good, she apologized and said she didnt see I was coming home. On wednesday their last lesson was cancelled and they sat in her car for 2 hours and talked and presumably kissed again. Yesterday we had a national holiday and she went to her parents house to work on her car, I stayed home and worked on my business. He drove 1 hour from his city to her parents house, picked her up and they drove to her dads parents area to go for a walk. She did that since we share our location and she wanted an excuse if i asked her what she was doing there (she said that). They kissed again.

Now yesterday evening she told me all of this, but I had to ask a lot about it. She didn't tell me they kissed, she said a few times that nothing happend but when I asked her if she could swear to me that the only talked she caved in and told me that they kissed about 10 times each date.

She swears nothing more happend but I dont really care. For me the worst thing is the planning that she did to keep it a secret and the fact that I told her, that I felt uncomfortable on tuesday and she went and apologized and told me not to be jealous when my unwell feeling was in fact right.

Something that just enters my mind is that she wanted rought intercourse on tuesday and kept on saying "punish me, I deserve it" - I asked her why and she said, that I shouldn't ask about it. Thats even more messed up in retrospect.

Yesterday she kept on telling me that she always felt bad after meeting him and couldnt stand looking in my eyes because she was carrying so much guilt, she also said that she does not want to break up, but she also does not really want to avoid her classmate, as he was becoming a friend of hers and she does not have many friends. I asked her if I did the things she did if she would consider it cheating (since they didnt get to the intercourse part - according to her) and she said yes.

The funny thing is, I was incredibly calm throughout the whole talk and am still not feeling a lot of emotions. I have small spikes in where I get a bit sad but other than that I just feel empty. Not angry, not sad, jsut empty and more so worried about logistics of our apartment.

The obvious answer is one I know - I can't trust her anymore and we should break up.

The Issue is, that we are both on small salarys (about 800€ /month each) since we are both apprentices. However she gets about 1k€ from her family and a government programm, so her income is about 1,8k. The apartment is 950€ a month including utilities. Both our names are in the rental agreement and if i remember correctly we agreed to stay about 3 years at least, until our apprenticeships are over. I will have to look at the details though.

I don't really know what I even want from you guys. I guess just some Ideas what to do now. If we break up, I will go back to my parents place. I don't need the appartment because my work is the same distance from my parents as from our current place. She however needs it as her commute to work would be over 2 hours.

So, I suppose my question is: What now?

TL:DR
Moved in with my girlfriend of nearly 3 years, but she recently confessed she’s unhappy in the relationship and has developed feelings for a classmate. Despite apologizing, she kept seeing and kissing him, lying to me about it until I pressed for details. Now I feel betrayed and empty, leaning toward breaking up, but we’re financially tied to our apartment lease, which complicates things. She needs the place more than I do due to her commute, but I’m not sure what steps to take next. Looking for advice on how to handle the breakup and logistics.