Problems with In laws?

So me and my mother-in-law have always had problems. Communication issues disagreements and certain things and all that. There's my problems in the past with me not feeling accepted into the family and we've been working on those problems the past couple years. I had my son 2 years ago with my baby's father who I've been with for 5 years. His daughter from a previous relationship recently moved in with us she's 15. I am her primary caretaker and we spend majority of our time together along with my 2-year-old. My fiance works overnight so he's usually not involved in a lot of family outings or dinners or what have you. There's also been some problems of me not feeling accepted with my fiance sister as well who would be my sister-in-law. We recently discussed these problems and have came to a resolution I thought about me feeling left out of the family and my mother-in-law said you're absolutely a part of this family etc. Long story short my mother-in-law and my sister-in-law have a family pass to six flags. She called and asked if my stepdaughter would like to go. It's going to be my sister-in-law's girlfriend My mother-in-law and some of the little cousins. So what I'm bothered by is my mother-in-law didn't ask if me and my 2-year-old would like to join them for the day and go out and have fun.. that really bothered me and hurt my feelings. I don't know what her thinking was I don't know if she thought maybe my son wouldn't enjoy it since he's only two. But they were saying something about going to a water park and stuff like that so I'm not sure why my son wouldn't enjoy those things. Basically my question is am I wrong for feeling hurt or bother by the fact that we were not invited? My fiance said that are 2-year-old probably would not enjoy it but I completely disagree. I am the primary caretaker for both children so I feel I know what they would enjoy more so than he would just because I spend more time with them and I know their quirks. Any thoughts?

Problems with In laws?
Post Opinion