I don't think you are. Be polite, be cordial, but you don't have to open your life completely to everyone. I felt very similar to you. Dad's are weird about their new wives... My brother lived a state away and rarely had to deal with her was like your sister and tried to guilt me.

All about me:

I was always happy that my Dad found someone who made him happy, but I wasn't interested in her as a personal friend and definitely not as a mother. She bitched to my Dad that I wasn't super chatty with her. I was always polite. (I was late teens early 20's so I am sure sometimes I was an asshole) We had nothing in common other than him. She was never a mother figure. He forced her on me and my brother as a mother figure. Telling us it would mean a lot to him if we acknowledged her on Mother's day, etc. her son was a loser, he sucks, can't we just send her a card? So I did, to make her happy. I resented him for it. It made me like her less, like why is so whiny about these kids she barely knows exalting her on her birthday and holidays?

It was a mistake on his part. We were too old for that bull shit. Our own mother was an asshole we had to deal with, we didn't need this needy woman we barely knew demanding things of us.

My Dad and I were very close, and I worked at his company for 7 years. We were probably too close at a point? She solved that problem. He wasn't capable of doing anything without her after they got married. I pulled away got a job elsewhere.

Our marriages were also really close together, I married 6 months after they did... this was 2001/02.

Then he died. Her friends told me that night that I need to take care of her now. I needed to step up and be her daughter.

(Reminder - she has a son. He's 5 years older than me. My own brother is older than me by 3.5 years . I'm the only girl and the youngest. My Dad was seriously her 4th!! husband - found that out much later when I was made the executrix or her will.)

I was offended... and.. I don't know, but I felt like a kid that night and had no one looking out for me, other than my husband and whatever.. he didn't know how to deal with this. My Dad died 40 days after his diagnosis. I was only 32. In a fucked up twist of fate I had put my 14 year old dog to sleep that morning... we thought he had a couple weeks left otherwise.. but she needed to go, she had hemangio-sarcoma. I couldn't hold onto her for me. It was the worst day of my life and these people were so fucking rude. I was numb.

Anyway, she tried to force herself on me further and threw this huge fit about us not being closer after my Dad died. I don't know why she expected it.. she would call my husband, but never me, about how I wasn't doing what she wanted.

Two years ago she made a rude comment about my bff being overweight and I told her it was rude to comment on people's weight and she was soooo offended she hasn't spoken to me since. She is obsessed with commenting on people's weight and I seriously that's all it took.. telling her it's rude to comment on people's weight.

I hear periodically about what a horrible person I am for random people, but I never told her not to contact me. I was polite but not overly friendly. The only thing we had in common was my Dad. She has more family and friends than I do... I feel guilty because she's an idiot and I know my Dad would want me to look out for her. I had every intention of doing so, but she's not my Mother. She's not my friend. She was my Dad's wife for 10 years. I was always polite and let a lot of stuff slide, but I was never interested in a close relationship and was always honest about that.

I have a lot of unresolved issues about my Dad dying - it broke my heart, and she made it all worse and tried to make it about her. I'm still mad at him forcing her on me.

Anyway, I don't think you are wrong. You get to set the tenor of the relationships in your life. Especially as an adult. I still resent him forcing her on me and it soured our relationship. If she hadn't whined and bitched to him, if he hadn't pressured me and if they had given our relationship time to form naturally we would have probably become friends, but instead I was put off by it all and now we don't talk.