https://humans.media/four-different-types-of-romances
Might be of use
https://www.psychologytoday.com/us/blog/the-mysteries-love/201701/the-11-reasons-we-fall-in-love
Also might help
But in the end, as a writer you have to figure out how to write 2+ characters that have enough character to make readers go "I can relate, even if I want to stab the damn characters" then make them relate to the type of love or romance you are writing (or just write really damn good so everyone can atleast say its well written).
For reference, I didnt read crap on either link, im just giving a copout reply cause I need to go and didnt want to say nothing!