AIO? Bf has been saying he’ll never move on from his (dead) ex and saying he’s not in a relationship when I thought we were for the past 2 years

I want to preface this by saying he hasn’t given me any reason to think he may be cheating, I know he had a lot of trauma in his past but he seemed genuine. However some of the things he said just seemed too good to be true. I looked through his texts and found all of these sent to a female friend I’ve never met. Apparently he had an ex who died (which I never knew about). These texts are showing him lying to this girl about who I am, saying I’m just a friend from high school when we actually met in college, and that he’s still not moved on from his ex, and only saying that he’s with me and wearing a ring (that I got him for our 1st anniversary and that he always seemed to love) so that other people won’t get any ideas. I just feel really crushed because he always told me over and over how much he loves me, how I’m super important to him, and how we’re going to get married one day. Now I’m just confused, why would he be lying about me like this and saying I’m just a friend and that he hates the idea of loving me? Is this something I should talk to him about? Should I break up with him? I’m not sure if I can live knowing that this is how he sees me, but idk if I’m overreacting