How would you react?

Okay so before I say I’m asking what you would think in the moment. I’m not asking for judgments.

So me and my fiancé had to take some space a couple months ago. Times were really tough and we were both struggling mentally and in the beginning stages of therapy. ( both of us have bad pasta and backgrounds )

Anyway, he admitted he was talking to other girls but we were split up and I tru to always remember that Cause it really fucks with my head.

Anyway, we are better then ever. Continuing therapy and making things work for us; our kids. It’s just been going great. He doesn’t hide anything from me. There’s literally nothing on his phone and I know he isn’t cheating or wouldn’t cheat. So last night we were sleeping and his phone was on loud and kept going off. It was his twitch notifications and I went to turn his phone on vibrate cause it woke our baby up, I noticed an add from this girl on snap. I didn’t think anything of it and I clicked on it and a bunch of old messages popped up ( from when we were split up ) I naturally just glanced and seen the word “pedophile”. I was like what the hellll.. so my fiancé is almost 24. This girl JUST turned 18 and she said in the message how she is a senior in high school and he was saying how he already graduated his bachelors degree and how he hoped it’s not weird for her and she was of course flirting back and his response was “ your so fucking hot, I hope I’m not a pedophile for this” like 😬😳

I mean she’s legal yeah but idk. still makes me feel weird, and the convo was like saved and it kept going on for him begging for pussy picture, tit pictures and ass pictures and how he kept saying how fucking hot she is and she kept saying dude “ I’m like 12..... jk” she said that over and Dover why would she say that? She sounded immature and as a child. I’m honestly now wondering if that girl is under 18. I felt guilty for reading them and I told him about it which he wasn’t upset. He feels bad that I even seen that but that convo I read just was not how he is. I felt like I was reading a typical fuck boy I’m high school trying to get laid and my fiancé is way more respectful and mature then that! I’m very confused what to do.

What would everyone do here?