I found
this article to be a thought-provoking read about why certain love interests work. As for Superman's romantic prospects in the cinematic universe, I think the biggest obstacle would be structural. I can't see a
Wonder Woman film -- her first live action solo film -- featuring Superman in any capacity, and I think for her to work writers of her film need to do some solid world building in her film, which means a supporting cast and possible love interest of her own. If
Justice League premieres first, then
Wonder Woman, and a
Wonder Woman film needs to be free to develop her without Superman, then I don't think anything meaningful between her and Superman can happen in
Dawn of Justice,
Justice League, or
Wonder Woman.
I also think in terms of writing and planning, movies require a different approach than comics. To develop a relationship between Superman and Wonder Woman in the cinematic universe would require lots of long range planning, collaboration, and coordination among the different writers/directors of the individual films in which their respective characters feature. It's been awhile since I've seen
The Avengers, but I don't recall it having a lot of time to develop any new love connections, and when couples were explored it was only pre-established couples like Tony/Pepper and Thor/Jane that got a mention. Then there's the issue of how much is a character's solo franchise diluted if it features guest heroes.
Batman vs. Superman is, from my perspective, a way for the studio to do a Batman film without doing a full Batman film -- something they likely didn't want to do given the too recent Nolan franchise.
Man of Steel was Superman's alone, and I hope that Wonder Woman gets to establish herself by herself too. By the time a genuine sequel to
Man of Steel comes around, I think giving Superman the spotlight will also be desirable. I don't really relish the prospect of DC's cinematic universe never allowing for the heroes to have their own franchises without other major heroes guesting.
I agree with others in this thread who are concerned about a break up would be handled between Superman and Lois. It seems to me that it would be difficult to design a break up that makes sense and that functions well as part of the storytelling (i.e. it doesn't damage the characters or undermine some of the world building already in place).