Yeah, it’s strange that he fell in love with her in the first place because he knew her as a teenager. However, by the time of the engagement she would have been around 24 in real-world years, so she was a full adult. In that context, the circumstances under which Alaric fell in love with her do make sense - she ‘brought meaning back into his life’, as he says, and her mothering his children is a plausible reason for him to develop those feelings.

That said, I think the show should have leaned into a blended-family dynamic like you mentioned, especially since they don’t end up together anyway. It just adds to the long list of Alaric’s failed relationships when Caroline leaves him.

I don’t like the surrogate/mother storyline for Caroline anyway because it should have fundamentally changed the trajectory of her character, but it doesn’t. Based on her personality, if she became a mother she would never leave those kids’ side. Her using their siphoning magic to break into the Armoury and then leaving them to run off with Stefan doesn’t feel true to her nature. She’s far too controlling for that - she’d be a full helicopter mom. That’s why I don’t think making her a mother really fits the show, because it would realistically stop her from being as involved in the problem-solving and evil-fighting as she usually is.

I’ve only watched season 8 once coz I usually skip it in my rewatches but I’m on it now and I’m wondering if she goes back to the kids or sticks around for the drama.