It's not only that you can't see the numbers, there are none. In civ5 there are no relations at all. Diplomacy is another element like religion or spionage they didn't like or have time to do.
Leaders will attack you no matter what you did to please them. Wouldn't even call it a backstab, just random reactions. Looking at what they say to you and how the react like another player says won't help either. One turn thay say you how they love you and want to cooperate with you, and 30 sec later they declare war. Like I said, don't bother at all, just expect any leader to attack at any time, and also don't think any leader which is angry will attack. Looks like a dice roll.