Am I being unreasonable?

I’ve been with my partner just over a year. In the last year I have gone through her phone a few times and found messages to her ex (the kids dad) saying she still loved him and stuff. I know I should never have gone down her phone but I did so we was both wrong. Lately I have had a really bad feeling that they are talking again so I asked her if I could see their messages but she said no and I need to respect her privacy. It even got to the point where I told her if I don’t see them I can’t be with her and she still said no. Am I wrong for wanting to see them or do you think she should show me?
Am I being unreasonable?
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