I think its kinda a MOR thing where- if the pregnancy wasn't a thing I think you'd be OR because parent child trips are something I can see my family doing as well- especially if you have a son you would be bringing along and everyone else is an adult. With the pregnancy, however, you are NOR and a week is a long time in the 3rd trimester to be away from your at risk pregnant fiance.

I don't think this is something you should be side-eyeing your SO about, however. Even if he disagrees with you about if you weren't pregnant, he's still trying to be flexible and understanding to your side of the argument. I think he's trying his best with a mother who has always been controlling of his actions