Looking for advice or opinions really as to whether I should just let this go.
A few years ago, DH and I went through a rough patch. I had just given birth and we weren't talking or coping very well. I had PND and was really struggling. Months went by and things seemed to get better. We even started to talk about having another baby and were in the middle of planning our wedding.
I was looking for some contact details for someone on DH phone one day and came across some messages between DH and a girl he is friends with at work. They were incredibly inappropriate, talking about private body parts, and very sexual. I ended up going through the whole chat history and they were talking about me, making fun of me being depressed (this was around the time I had just had our son and I was incredibly unhappy). There were also messages between the two of them from a business trip they both went on which seemed to imply they may have slept together.
I was so shocked and upset. I confronted my DH. He got angry at first because I had looked through his phone, but he calmed down and we spoke about it. He realised I was devastated that he had been talking to this girl, but denied anything sexual happened despite their texts. We eventually got married and soon after had another baby. Though this was a couple of years ago, I just can't let this go. I am very often angry at him and whenever we argue I bring it up again. He keeps saying he's sorry and he knows it was wrong to talk to her. But feel like I'll never know the truth and that I can never really trust him again. Do I just let this go and accept that I'll never know for sure?