99% inlaws are like this only. Even if they don't like their DIL they want her to spend the whole vacation with them. Out of 15 days of your vacation even if u spend 14 days with them and thought of spending a day with your parents then they will show their true colours again. So best way is to ignore their taunts as much as possible and stick to your original plan. If the situations are getting worse you can cut short your days at inlaws place ( 6 days to 2-3 days) and spend more time with your parents. Even if you stay with your inlaws try to spend maximum time outside the house by going for shopping, religious places or one day trips. Just roam around the place full time so that you can avoid their unwanted talks to an extent. As your DH knews the real face of his parents you can very well carry on with your vacation plans as decided. Ask your DH to clearly state them that you people will plan your vacation according to your convenience only and there is no point in asking their opinion for booking tickets etc.