Well, you must be suspicious or you would not be asking the question.
Clues to cheating concerning personal habits:
#1 clue is A Change in habits,
Doesn't come home at the times he used to,
Says he hanging out with friends or going places with friends more than he did before,
Say he has to work late more,
Finds a reason to get out with out you. more frequently,
Has cell phone conversations in the bathroom or at the back of the yard ect,
Seems jumpy when his cell rings and you can hear it,
Anyone else think of anything else? .
Chuck him and find a new boyfriend.
ask him upfront
you catch him out.
If you can forgive your sister, you can forgive your boyfriend. It doesn't necessarily mean that you should stay with your boyfriend. Cheating is cheating and if that is not acceptable to you, you should find someone who will respect that wish.
by asking your best friend to spy on him
not spending time with you and maybe not sleeping with you
No it is not cheating on your bf. As long as nothing physical happens your not cheating.Talk with your boyfriend about how much you're allowed to do with other guys without cheating him. Everyone has different ideas of what cheating is and what matters is that you two find a common ground and agree not to break that.
Maybe
Find a new boyfriend. If he did it once and you forgive him. He'll do it again and expect the same.
there probably cheating on you
If you have a girlfriend and a boyfriend, then you are cheating on both of them.
Then do nothing and be glad he is no longer your boyfriend.