语法是没错,但没人这么说,这是典型的中式英语,不符合英文的语境和习惯。有事要先走的这样的情况,说句"Excuse me.I have to get going.You guys have fun."就足够了。
像"I have to leave now cause I have some personal matters to deal with"之类的,除非有急事要临时跟老板请假,或者事先约好的活动不能到,才需要这么说。不信你试试,没事的情况下对西人这么说,他们一定一脸紧张加关心地问:Are you Okay? Is everything alright?