How do I 22F, talk to my boyfriend 27M about lying about circumstances regarding his Ex.

r/

I 22F and my boyfriend 27M, have been together since December 2024 (this is relevent). My boyfriend has a child 3M from a previous relationship. This relationship ended messy with custody cases and all, they were never married and she broke up with him way before the child was ever even born. I have never been with a man who has kids so this has been a new experience that opened new and old insecurities. 2 months ago when my boyfriend and I finally said I love you to eachother we had a long talk about these insecurities and he reassured me that he didn’t have feelings for the mother of his child anymore. He told me that she has asked him to get back together in the past and that he “couldnt do it, because of the betrayal”. I trusted this. Well, About 2 or 3 weeks ago I went on his phone and read there messages. Im not proud of this. He never says im not to get on his phone but we dont make it a habit to go on eachothers. (I know this sub reddit tends to go after people who go on there partners phones, im aware It’s unhealthy and shows a lack of trust. Im working on it.) Sometime in novemeber 2024, the mother of his child messaged him asking to go out to dinner together and get back together and be a family again, said she still had love for him and everything. My boyfriend said in his reaponse, that they couldnt be around eachothers family’s yet but they could see where things go. There was more said in these paragraphs that doesnt have much relevence. The main point is he said they could try and work things out. After those long paragraphs there was no more messages that suggested anything. Either they had been deleted or they communicated over the phone. But, To me, in this case, if its not an immediate no, its a yes. I feel like he lied, and that this solidified my fears about there still being feelings involved. I dont know how to bring this up. It’s been eating at me for weeks and just keeps making its way back into my head. How do I bring this up? Clearly something happened during that time frame.

For clarification my boyfriend and I had been talking since October 2024. If that means anything.

TL;DR; : I went through my boyfriends messages with his Ex and found out he lied. How do I bring this up?