How you know yo man cheatin or its just u

males advice too please!

lolz well you can never know for sure, but if you give me reasons why you think he is cheating then I am sure I can help you out.

-He's acting a little weird (I.e constantly angry, frustrated)
-Spends a lot of time with someone else he doesn't like to tell you about
-Lies and goes somewhere else instead of where he told you he was going.

Just things like that. Try not to get paranoid though.

it could be many things...add a little more details

-smoking
-acts distant

it doesn't necessarily mean hes cheating, he might not be happy in the relationship anymore. you weren't very specific.