My men is very sneaky?

my men in i are staying with a friend in his friend had 1 of his female friends come here from out of town in they all went out to the club in my sister goes to the club where they go all the time so she told me today that my men in the female were with each other the whole time in he was grabbing her hand. in lately he been real sneaky talking to the girl alot looking at her in she been doing the same. he was walkin around with his shirt off in the whole time she was here he didnt show me attention in now shes gone so now hes all over me but now im very angry with him he wanted to have in i refused. so should i be mad or know cause now that i know hes sneaky i cant trust him so what should i do.