Nick and Adalind never got married in the show. Like Tlc20 said, they probably got married during the 20 year gap in 'The End'.

Does Nick end up with Adalind?

To her initial dismay, Adalind becomes pregnant with Nick's baby, while Juliette turns into an evil Hexenbiest. ... It's awkward, sure, and Adalind wishes she could take back everything she did to Nick, but their romance does eventually blossom.

What episode does Adalind love Nick?

In episode 12, before leaving to fight Zerstorer, Nick does say it to Adalind. It was one of the best highlights of the final episodes for me and I love the way Nick closes his eyes when they hugged before he departs.