F28 M29 trust issues and called it off with me

Was I wrong here or was I just overthinking?!

For context, there had been incidents earlier in our relationship that damaged my trust, so whenever another woman became involved in any way, it would trigger a lot of anxiety for me

The final argument was about one of his male colleagues and the search about a girl from his work place

About a year ago, I was logged into his Instagram account (which I’m pretty sure he knew about). One day I checked his search history and saw a girl’s profile I’d never seen before or heard him mention. I clicked on her profile and noticed she worked at the same place as my ex. Naturally, I had questions. When I asked him about it, he saw my message, deleted the search from his Instagram, and didn’t reply for about 10 minutes. I don’t know if he was anxious, trying to think of an explanation or something else

When he finally replied, he said he hadn’t searched for her. According to him, one of his male colleagues had asked to use his phone to look her up because he was interested in her and had apparently been blocked by her. My ex said that was the reason her profile appeared in his search history

What made it difficult for me to believe was that there were several colleagues around, yet apparently this one colleague chose to use my ex’s phone. Whether that’s true or not, I honestly don’t know, but it became one of the biggest sources of mistrust between us

Because I didn’t believe his explanation, and I wasn’t getting enough reassurance I ended up messaging the girl. I know some people will probably think that was crazy, but I’d invested three years into this relationship and we were planning to get married. I felt desperate for answers.
I sent her a DM without mentioning my boyfriend’s name. Surprisingly, she immediately guessed who I was talking about and asked me to confirm if it was him. I said yes

She then told me it could never have been him and that it must have been his friend who had searched for her. She reassured me repeatedly that I should trust my boyfriend and said that if there had been anything between them, she would have told me herself. However, there were a few things that confused me. My boyfriend had originally told me they had never spoken, never interacted, and didn’t even work on the same floor. But she told me they worked on the same floor, that she’d seen him around, knew who he usually had lunch with, and seemed to know quite a bit about him. Later, my boyfriend admitted he had seen her once or twice, even though he’d initially denied it. Another thing that made me overthink was that while I was messaging both of them, they both went offline and came back online at almost the exact same time. I know that could be a coincidence, but at the time it made me even more suspicious. Even though she reassured me throughout the conversation

so yesterday I told my ex bf During the argument, that I was going to message that male colleague directly and ask him myself. I never actually sent the message, but I told him I did. He became extremely furious about that and basically ended the relationship over it. From his perspective, I crossed a line by involving someone from his workplace. From my perspective, I felt so desperate for answers that I didn’t know what else to do. I wasn’t trying to ruin his career I just wanted the truth because I felt like I wasn’t getting it from him. He kept telling me it’s not him this is the wrong person yapyapayap but I’ve already done my research and it is this guy 1000%

well he ended things I don’t know if he really did mean it or was it just in the heat of the moment. Anyway Part of me thinks I should just let it go. Another part of me thinks that I’ve already lost the relationship anyway, so if messaging the colleague would finally give me answers, maybe it’s worth it.