context: I met my girlfriend in college through Tinder. We started off with different goals—she wanted something casual, and I wanted a serious relationship. We both knew this, but we kept talking. Over winter break, she started replying less, so I decided to confess my feelings. After that, we spent more time together, and things got serious. She told me she wanted an open relationship, which made me nervous because I’m a jealous person, but I agreed.

The first six months, we didn’t explore the openness much, but by junior year, she wanted to hook up with other girls. We set boundaries to make it work, but I struggled with jealousy. Then, she went abroad for a semester. We agreed on long-distance, but she later told me she needed a break due to relationship anxiety. I was crushed and struggled deeply, especially when I found out I had a stomach tumor. Despite my surgery and recovery, she barely checked on me, which hurt.

When she came back, we tried to move past the pain, and our senior year together was wonderful. We talked about our openness often, but they were uncomfortable conversations. After graduation, she went on a solo trip to Asia for six months. I wasn’t thrilled about the distance, but I supported her. The first few months were rough for me, especially since I had just moved to a new city and started a new job, but I thought we’d be fine.

Now, about a high school friend: We’ve known each other since junior year. We never dated, but there was mutual interest back then. Over the years, we stayed in touch, and I confided in her about relationship struggles, including my discomfort with the openness in my relationship. I regret sharing personal issues and venting to her about my girlfriend in an inappropriate way.

One day, my friend reached out, and we hung out. She confessed she still liked me, but I told her no. My girlfriend had recently told me about hooking up with someone else, and I was overwhelmed with jealousy. A week later, my friend asked to see a movie, and I agreed, but I backed out when my girlfriend came back into town.

When she returned from her trip, everything felt great until November. She used my phone and saw texts between me and my high school friend. She found messages where I was flirting with her and venting about our relationship. She accused me of emotionally cheating, and I couldn’t defend myself. I had lied by omission, keeping my friendship with this girl a secret. We’ve been fighting for the past month, and I know I’ve broken her trust.

She’s leaving for nine months abroad in February, and we agreed to stay together until then, but I can’t stop feeling guilty. She still loves me but needs space to heal and forgive. I’ve apologized as much as I can, but I don’t know what else to do. She’s my best friend, and I love her more than anything, but I feel like I ruined everything. I need to change for both of us, but I’m heartbroken for causing her pain. I don’t know what to do next.