LW, do not let your fiance and his awful family neg you into going on this trip. And if your fiance pushes back on your very reasonable boundary of "No, I will not spend time with those terrible people, but I won't stop you from seeing them if you like" or if he's ever participated in these hate-fests - break it off! There are actually nice people out there who don't spend their free time talking about how they hate all their inlaws, or at least hate the men and the women equally.