Actually, it's quite easy to find out with whom you have pacts of secrecy and/or pacts of cooperation. Just click on the diplomacy button in the top right of the screen, then click the Global Diplomacy button that pops up there, and on the screen that pops up, there are three tabs. The one on the right has your current pact information.
Yup, and then if you want to drop the pact you can by talking to said leader again and going back to the discuss page