We have joint phone and he does not know I can check his calls and texts. I knew every number but 2. A cell number and landline
How do you know he doesn't know you can check this? If he IS cheating on you, he'll be typically pretty careful/paranoid, and he'd probably check to see if you had detailed billing on this account or not before he got all careless with it.
I suspect they are using the cellphone and the landline merely to set a time/place for some other form of contact (hence the short call durations). Probably instant messaging on his computer?
