Well, if ur partner has all of the above mentioned, and ur "still not sure"...then you've got a screw loose....
Sometimes they'll keep "looking" at their watch, makes you feel they don't want to talk, haven't got the time for you.....come home very late and say "Don't start"! I'm very tired"! and go to bed, closing the door...if you really know ur partner, then you can spot the tell-tell signs. They avoid the issue when you quiz them about "what's going on."
It's emotional abuse, they're ashamed of what they are doing (cheating). But instead of sitting down to talk about it, they won't, keep putting it off......So, it leaves you in "limbo", not really knowing if he/she is cheating or not!.....making you feel bad that you "suspect" something is going on but can't prove it.....Sometimes you have to do a little detective work on ur own.