im so sad

in 2022 I met a guy who quickly became a dear friend. After a short time getting to know each other, I started feeling confused about what I felt for him, I couldn't tell if I liked him romantically or not. I talked about it with my girlfriend and she said that if I wanted we could break up, but I told her no, I wanted to stay together. It was something that troubled me a lot and I genuinely couldn't figure out if I liked him or not. Sometimes I'd tell myself with more certainty that I didn't, but then the doubt would come back. Our friendship was something I cared about deeply, we were also very affectionate with each other, though sometimes specifying that the affection was platonic and nothing more. We also often made very sexual jokes at each other's expense, often very silly ones, but not always. His attention made me feel good, he'd often compliment me and I felt appreciated. I liked the idea of him seeing me as an attractive and interesting person, and I actively wanted that. Over time the doubt faded and I stopped wondering if I liked him, it was very clear he was just my friend. Years later, in mid-2024, I started wondering if during that period I had cheated on my girlfriend, if I had said something with wrong intentions or stuff like that. Nothing physical ever happened, and when we would hang out I have no memory of wanting to kiss him or anything like that. Initially I told myself it probably wasn't like that, nothing came to mind and those sexual jokes didn't seem like anything strange because I couldn't remember any wrong intentions. Over time the doubt grew, until at the end of 2025 I became convinced I had acted with wrong intentions. There are many conversations between me and my friend that I now consider ambiguous or proof of cheating The problem is that I told my girlfriend everything, and she doesn't believe me, she thinks it's just OCD. This has caused a real rift in our relationship because we're on completely different wavelengths. It's hard to be together. I've become more absent at a time when she's not doing well and needs me, which makes her upset But I'm convinced I did something wrong and I don't know what to do anymore. It feels like our relationship is built on a lie that she's ignoring. I want to cut off contact with this friend( who also thinks it's just OCD) even though my girlfriend told me I shouldn't. I feel totally convinced now, and it makes me deeply depressed because she's the person I care about most in the world and I can't bear the thought of having done something so terrible