I am writing this to mainly to check myself, and get perspective for myself. I am wanting to know if I am overreacting or being hypersensative or a wuss.

background:

My wife and I have been together for over 12 years, she has a 20 yo and 16 yo, which I really hate the elder one. it has been a long road, and I will admit I have been the jerk in some situation. Her eldest and I are oil and water, since she was 9 yo. She still hopes her parents will get back together. Her youngest and I got along pretty good when she was 4 yo, but we broke up because my suspison is that the hubby instructed her too. The youngest and my relation didn't survive, she was a brat after my wife and I got back together. We agreed that my wife will do the displining and raise her kids, I don't know if that is ex-hubby instructions or what. We do a lot things together, her ex and us. I think it is freaking weird! My wife takes care of her ex's daughter him and his wife had together. She is a good kid, but tends to act like their daughter's mother, which she is a super B, which I will call her. The super B, has no friends, super insecure, low self esteem,  acts tough to over compensate, nobody in my ex's family likes her, everyone tolerates her. She has rubbed off onto my wife's daughters. The eldest daughter does not get along with her lifelong friend, becasue she is alway rubbing her wealth in my wife's eldest daughter's face. I promised my wife I would get her a truck, and I did. I screwed up and got a lease. Happy ending, I paid off the truck, I kept my word. Well, we traded in the lease and got another truck. My wife tells her eldest daughter that we got a newer used truck, around 50k mi's. My wife was proud about the deal and truck. My wife's daughter goes, "Did E (me) talk you into getting another truck?" My wife answers, no picked it out and I got it. My wife said her eldest just made a face. Why couldn't she have said, "Cool mom! that's great!" But that is the my wife's ex's wife reaction to any situation where good does not happen to her.  My wife's youngest daughter is turning out to be the same way. My wife states that her daughter are not hers, because they act like her ex's wife. Yesterday my got off work, said she is tired, her youngest asks her to go to homedepot to look at flowers, my wife says no. The youngest proceeds to instruct my wife to ge in the truck and go. Pissed me off, however, not my monkey, not my circus! If I step in all it is going to be is a fight. She also has major daddy issues, I say that as an observation, not a judgement, or spite. 

Situation:

We all do everything together, camping, b-days, new years, Thanksgiving. We call ourselve a family, but they just invited my wife to go to SLC. I am kind of pissed, I don't know why? I really don't like them, the ex is...there is no nice way to say it, a moron. I hate his wife. I do like their daughter though, she is a hoot, except when she acting like her mom. I tolerate my wife's girls. The eldest girl's boyfriend is a lemon (as in this car is a lemon) and a braggart red neck. So, why am I pissed? 

like everything else, this too shall pass

Thanks for listening.