About two months into our my partner and I relationship (the first time) we started having the crazy ex talk. He started talking about his last gf who had cheated on him and had been broken up for around 8 months. I started to get a weird feeling about them when he said he was going to catch up with her for lunch while she was in town (the lunch didn't end up happerning) One day we started talking about how and I said how it made me uncomfortable that he wanted to see her after what she had done to him. He said he hasn't spoken to her after her trying to meet up. I had this weird feeling in my stomach and I did something I always promised myself I wouldn't do....... I looked at his phone when he was in the shower. I found a lot of text messages dis robing what they wanted to do to each other (sexually) and that they had been snapchatting nudes to each other. I cried so much. I didn't know what to do. I was at his place an he away from mine. No car. No friend or family around. I took a pic of some of their conversation as I just couldn't believe it. I went into the shower after him as I was just speechless. I cried my eyes out for around 10min. I go out and I confronted him. He must have sensed that I was worried about his relationship with the ex as he deleated all the messages.  He said it was nothing they haven't talk. When I showed him that I took pics of the convos, the truth came out. They had been doing it only for a week or so beforehand. I was shattered. I loved this man and he could do something like this. I walked out. I walked to the closest train station and took the 2hra train home rethinking everything that had happened only an hour ago. I did not speak to him for more the. 8 weeks. He wrote me letters, telling me how sorry he was and that he couldn't believe what he had don't and that the ex just had this hold over him. He told me that he blocked her from every social media and told her to never contact him again. For some reason I forgave him. I looked passed what he did because I loved him. I believed him that he would never ever do anything like that again. We have been back together for about 3 months when on the weekend we had been drinking and he had told me he had a missed call from the ex. My heart sunk. I cried I thought it was all happerning over again. When I asked him if he had talked to her at all he just shook his head but didn't say anything. I would really love some advice if possible. I can't talk to my friends about this as they hate him already because of what he did to me the first time. I just don't know if I believe that he hasn't spoken to her or that he is playing me. I need your help. Please.