You can't actually have a romance between friends. That sort of defeats the definition of the word "romance." The word you're looking for is "love." It's a love between friends, just as there's also love between lovers, or possible lovers, or even ex-lovers. Same holds true for "bromance" - it's just a clever word used to avoid the word love, for straight boys who don't want that old-fashioned taint of gayness. Dudes, you love each other. Deal with it.