I don't recall noticing an actual romantic relationship ever materialized, and then of course, out of nowhere they hooked her up with Chakotay

.
Yeah, that Chakotay angle was complete bull.
Did an actual romance ever materialize between them, or did it never go any further than just hanging out and learning about their humanity from each other?
The Doctor professed his love for Seven in "Renaissance Man" when he thought he was going to die, and got caught daydreaming about her in "Tinker Tenor Doctor Spy". He first fell in love with her while teaching her to dance in "Someone to Watch Over Me". She never reciprocated those feelings, but he was clearly in love with her.