Am I being irrational?

Im currently 17 weeks pregnant. Me and the dad have been solid up until I got pregnant. About 2 weeks ago we called it quits, or more like I did. I had found he was entertaining a woman on tiktok a few months back. Im late to finding out, but I did all the same. We sort of worked through that even though Im still extremely insecure about it. We tried rekindling this past weekend when I found him watching those spicy content creators on tiktok showing off their increible bodies. It wasnt just one, or two, or even 3. It was more like a handful and I freaked. He says I have no right to be upset because we werent together but it hadn't been a whole week and he was already watching that. My question is am I overreacting and being irrational?