All of the things you've mentioned are things that my husband was doing as well- with mine, it did turn out that he was having an affair with some bar skank. Hopefully it's not true for yours, but it's time to find out.
You need to install a keylogger on the computer. Start there if he's always on Facebook. It's easy- you don't need a sophisticated one, just a very basic free one. Just Google 'best free keyloggers' and you'll find many options. I used one called Family Keylogger. You just have to be sure to read the instructions and click the options to make sure the keylogger is hidden. You select a series of keys to push to bring up the hidden icon and view the logs. Then you can see what he's typing on Facebook/email, get all of his passwords, etc.
Do you have kids?
Last edited by RoughTime; 08/04/1012:29 AM.
Me-29 H- 28 Together for 6.5 years 2 kids, ages 9 and 5 D-Day: July 15, 2010.