I think there's plenty.
NSFW-Studios' story "Starcrossed" is the first that comes to mind, as do his characters Sylvia and Madison.
For the record, Calina and Tan belong to Frenchsnack, not Timing2. All he did was commish them.
Archmage_Bael's namesake is involved in one. He goes by Anduril_Wielder in dA.
BonazaiGirl has a naga that adopted a young boy. I don't remember if she's written any stories about them already.
CeeNova wrote one of the few M/f examples- with Cass and Jazz, two of her usual characters.
Dante8411 wrote one with Phoebe Phobos, in the story of the same name, and continued in Worst Succubus Ever- ongoing, though finished now.
Dracosa wrote another M/f example- or rather, drew.
No mention would be complete with EroGG's Worst Succubus in Hell.
God1240 had a fairy join the party.
Goldclaw's Luna's Tale has some of that. Though I don't know if you'd find it romantic.
Gt500x is working on Torin island- he's yet to write anything, but a lot of guys marry giant harpies there.
If friendship alone is enough and you understand French, go for Gwadahunter's stories involving Faoran.
Johnathans223 has a guy linked to a dryad.
Krisexy26 can be counted on for that, with her characters Luniela and Paul, which are in Felarya.
Lyiba_Mooneyes' Willow isn't that big yet. But she'll grow. And grow. And grow.
Maelstrom14 has his namesake becoming a big brother to a certain Brenice.
I think Malnorm has tried this concept...
MrNobody13 did it with Swiftlit and Calimn. Nothing hot, but it should do it as far as romantic goes.
PrinnyDoodAbides has a gentle elemental. I wonder where things will go from there?
The Archvile has a promising situation in his The Sojourner series.
Tora044's girls all have friends.
Turboman500. Just... Turboman500.
I think that'll be good for a start.