We've finally settled down enough to start watching Game of Thrones (now that it's ending!) and it occurred to me that George R.R. Martin does not have a problem with throwing his characters into conflict. Not even if it kills them!
As for me, I find it very difficult when writing a sweet romance to have an interesting conflict, something that's not too tame but not too far out. So I started writing down where I get inspired to find conflicts that shake up my creativity.
If we look back at Game of Thrones again, we see a lot of betrayal. Well, no matter what kind of book you're writing - even a sweet romance - there is some level of betrayal that can work for your story.
I have more examples from The West Wing, children's fables, children's books, the Bible, and poetry. I hope this episode gives you some great ideas for introducing more conflict into your stories, or finding new ideas in general.