AIO for ending a 5 year friendship because of her boyfriend?

This is going to be long, and I'm gen sorry for that. I'm going to start this off with the fact that we're all teenagers, which I feel like should be important to the context. My friend, 19F, met this guy, 22M, online in an RP group on Facebook. They pretty much hit it off right away and have been dating since February this year. My friend group didn't mind that we practically didn't know much about this guy, or that he and my friend had never met, and she's already very much in love with him. Who hasn't had a long-distance relationship once in their lives, right?

Well, the problem wasn't that. The problem was, just 3 weeks ago, my friend came calling, crying because, apparently, the guy lied. He has a daughter. A 5-year-old daughter, whom he kept secret for MONTHS, because he was scared and wasn't sure he could trust my friend yet. According to him, he had it with his then-girlfriend (now ex), and they're currently just co-parenting. My friend sent a picture of his daughter and said it looked very much like him and that it genuinely hurt her. Right off the bat, every single one of us told her to break up with him because that was a huge red flag, and we felt that it was manipulative. Also, I've obviously read those stories from Reddit with that same situation.

She said she couldn't break up with him, that she loved him so much (mind you, they haven't even met irl yet and didn't know him that well despite months of online dating), and that he hasn't done anything to really hurt her. That it was just an unfair situation for both of them. We had to remind her that he literally lied to her face, and his words felt manipulative.

She left us on read, and then the next day she came knocking on my door, hysterical and literally sobbing on the floor because she broke up with him. She said she couldn't take it, that the situation really hurt her. I was there for her, obviously. I calmed her down, listened to her, and gave her something to eat because she hadn't eaten anything all day. This was where it started to dawn on me how I might not really recognize my friend anymore. She went on to say then that she broke up with him not because he lied, but because, and please keep in mind that she's 19, "couldn't stand knowing that WHEN they have a kid together soon, he wouldn't love their kid as much as he loves his firstborn." She said she googled it (lol), said that she couldn't stand that she'd have to love his firstborn as well.

I was mute for a second. Because what? Keep in mind, she was never like this before. EVER. Despite that, I was just glad that she removed herself from that matter.

Until the guy texted back that night, and she was just so fucking taken by him that she took him back. None of us could understand why, my other friend and I agreed; she might be getting manipulated, and there's just nothing we could do. We reiterated that we don't support the guy and his actions, and we think he's a big liar and a manipulative asshole, but that we still love her and we're here for her, whatever may happen. She said that she didn't care, that she could go to hell for her decisions, and that she doesn't mind because that's how much she loves this guy. And oh well, okay then. We thought we left it at that, until she reposted a TikTok about how, to make your partner feel comfortable and to make your relationship last, you have to give up people who go against it-- that it's called growing up.

What the fuck. Bear in mind, we've been friends for 5 years. We've seen each other's worst and best and have always been there through it all. We've always valued our friendship, and she knows how much I treasure our bond.

So I sent her a long message explaining that I just don't think we could be friends, especially since we don't have the same mindset anymore. Was I overreacting?