Can i ask my boyfriend (best man) details about his brothers bachelor party?

UGH NO!! if you trust him so much then why be so insecure? I'm not a guy but I do know that no matter what a guy is always going to look at another attractive woman and even in some cases may casually flirt with her. Its no problem until he acts on the attraction. So there's no point in you nagging him about it. It will just push him to the edge and he'll do it even if he wasn't before and think "we'll shes accusing me of it anyway" Guys hate jealous women. As a woman you should know this! I am 21 and know. PS my dad cheated on my mum with one of her best friends that doesn't mean I going to turn into some controlling jealous girl!