Happened to me twice so far in my three relationships (Really great for my confidence I know) In both instances they assured me that that guy was just a friend and blablabla. I had a bad feeling about it every time but I „allowed“ them to stay in contact because I didn’t want to be an asshole and I trusted them. Then eventually both of them got very defensive about their text messages and tried hard to hide their phone from me (I never search through my partners‘ phones, but sometimes a side glance on a pop up message can happen I guess) I don’t know what happened to my first gf because I didn’t want to keep contact after that. The second one was, what I thought, „the one“ and it was very hard to get over. I don’t think she’s happy rn though I hope she is. In her instance it was an ex bf she got in contact with again when she visited her family without me for two weeks. Although she had told me that she never really loved him and that she loved me more than anyone ever, that didn’t seem to be the case. They got back together and as far as I’m aware they’re still together now (should be a few months now).

I‘m currently single because I kind of have trust issues now I guess. It made me feel unworthy to keep a healthy relationship and although my friends tell me otherwise, I feel unattractive, unwanted and hurt. But that will fade eventually (probably)