Here is my description of the book:
Borrowed from library mid 1990s, a children’s picturebook. It’s title may have the word “love” in it. 
A little prince character called something like “Prince Curlique” (but I’m not sure of the spelling) because of his crazy hair/a curl  (sticks up?) on his head. 
He’s really smart but short or ugly or some unfortunate attribute.
He might get lonely and seek a girlfriend at some point, has sort of a love triangle with two princesses who are sisters trying to decide which one to marry(?)
He’s prone to being a bit harsh and testing his potential love interests if iirc
One princess is called Mira or Myra because she is an admirable yet unattractive genius level smart girl. She is the obvious match but his heart leans in other directions. The other princess is called Dora because she is an adorable hottie, she is however cursed with being clumsy and possibly unintelligent? Or inarticulate?
The ugly little prince curlicue guy and one or other of the princesses are pictured on a swing or seat together maybe on the final page?
The illustrations are very whimsical and to my memory lush and detailed, with historic rococo style maybe.
There is one page with a drapey princess canopy bed i think? The book starts with some of the characters as babies?
It’s kind of inappropriately romantic for kids in a way like that naked squashed fairy book from the same era because it’s about characters falling in romantic love with each other and the relationship stuff.
I think Mira/Myra is in love with Curlicue but I don’t think she prevails because of not being hot like her sister. I think one or other sister is also grossed out by him and that might have had moral repercussions.
There is some witchcraft involved possibly but more like the hand of fate because I don’t remember an antagonist.
I think Dora was Dancing and stepping on people’s toes because she was so clumsy 
Curlicue had red or blond hair.
Any of these remembered details may be somewhat incorrect. 
If I had to make comparisons, the alt love story of “Jane and the Dragon” is a well known one that’s vibe has similar whimsy. I think Myra was quite a roll-up-your-sleeves and get it done person and the art was similarly soft and evocative. The writing was dreamy and aphoristic, possibly why the story has not stayed on the shelves. But also something dark and sad about the characters’ difficulties finding love. 
I know beautifully illustrated kids storybooks are on high turnover in my library now, but they did have it once, would they have a record of decades-back purchased, now cancelled, books? Also I’m not sure if the high turnover was as rapid in the mid to late 1990s as it is today, so conceivably this book was 1980s at the earliest and just hung out on the shelf not getting borrowed much. The style would not have been any earlier based on the production techniques and the fact it was a fresh edition that we borrowed (but now so unknown to the internet that it must not have had many reissues if any)
I think that’s all I can think of that’s relevant. I would have said the book had a square format, normal picture book length  and possibly a soft cover no dust jacket? I’d have said slightly gloss paper rather than matte But I could be wrong about the soft cover.No idea of the publisher. If I had to guess would have thought the author might be American rather than British but that’s not a strong conviction.

I have a feeling the name curlicue is a total red herring and it may have been “Prince Quiff” or similar. But it related to his hair and unfortunate looks. The love interests’ names I’m more confident of because of their in-narrative meanings.