Do you trust him? I think that each relationship is different. If you trust him to go on a vacation, maybe that's all that it is, a break- a vacation to relax. But if you're worried, is it something he's done in the past that makes you not want him to go? I would write down your thoughts or think about it for a little bit before approaching him and maybe having a conversation about it. Either way, everything will be okay. Just stay strong!!