I was recently involved in a writing class put on by Bold Strokes Books, and they had an interesting approach to writing conflict within romance stories.
When writing a romance, many writers need to rethink their entire approach to the story. A romance is NOT about two people who meet and fall in love. It is about how two people who are perfect for each other, can't find a way to be together.
When writing romance, don't think:
I write stories about people falling in love.
I create love-starved characters and torture them for 300 pages, making them (and readers) think that they'll never have true love. And then in the end, I give them what they need.
Then when you begin to write, START WITH THE CONFLICT, not the characters, not the setting, not the backstory, not anything else. Too often, authors start with interesting character backgrounds and then try to build conflict from those characters. The conflict is the hook, start with that.