I’m confused. When did Adalind fall in love with Nick?

Well, anon, it was…

Huh.

You know, that’s a really good question. They’ve only been living together for a few months, tops, and during that time they’ve been somewhat under siege. Not the best atmosphere for developing any kind of healthy connection.

Before that, she was emotionally manipulating him into protecting her from Juliette.

And before that, she was raping him and stealing his powers at Viktor’s behest in a misguided attempt to get Diana back.

Funny…it’s almost as if this whole thing between them happened way too fast and without sufficient development for it to make any kind of sense to anyone not watching it through shipper goggles.