I don't remember the names for sure. I've thought of a few "was it this?" heroes names: David, Stephen, Francis. The heroine, I keep thinking of as Julia (or some variant on that). But I wouldn't eliminate a book that you might think of with a hero or heroine's name totally different from these, because I'm really not sure. It's funny, usually names are what I remember most about a romance novel, and that's how I'll think of that book ("Oh, that one's Catherine's and Michael's story," or, "that one's Lucien and Beth's"), but I guess it's been so long since I read this one that I don't remember the names anymore. I seem to think that the hero had a somewhat weak male name to go with his portrayal as initially overweight and a bit weak (even though those changed), but even this I'm not sure about.

I also think I remember something about the heroine wearing a yellow dress in the beginning scene?

No, nobody's PMed me yet. I guess this is a hard one!