That may be the reason I didn't enjoy The Time Traveler's Wife. I found it depressing, not just sad. It also combines many different genres and is confusing as a result. It was a Back to the Future type of fantasy, plus a tragedy and a romance, in addition to being science fiction (with the seriousness of Frankenstein but without the horror aspects). I came out of the film feeling unsatisfied and a bit distressed, as I had been looking forward to an entertaining afternoon with the likes of Meryl Streep in a film about cooking.
I haven't read either book as yet. Maybe The Time Traveler's Wife has really excellent prose, and there may even be pathos in Julie and Julia, which I plan to read. I may skip The Time Traveler's Wife, but I know many readers will want to read it for the same reasons I didn't like it in the film.