Jaime has definitely let me down too
On a side note, he was in my small town earlier this month filming a movie and I caught a glimpse of him
In the books, it's different because you know the character's thoughts - Jaime became well aware of Cersei's numerous other lovers, and in the books at least it seems as if he doens't love her anymore. I hope George does finish the books and we can see how he intended things to play out if different from the show.