You should go. You should also probably actually have a full discussion with him about this. I'm sure he felt/feels hurt and uncertain about how to act around you going forward in the same way you felt uncomfortable and unsure with him going forward. I'd go to Thanksgiving, act normally, and then pull him aside at some point to have a frank conversation. You're understandably uncomfortable, but it's also understandable that he'd feel hurt and maybe a bit blindsided since you do get on now as adults. (I say this as someone who also has a stepdad I get along with much better as an adult than I did as a kid)
I would go for your mom and sister. About your stepfather, I would certainly go to therapy to understand what was wrong with him and how to navigate this situation. Motherhood will reveal to you some hard stuff for your mind and therapy will definitely help you to deal with it.
Do whatever you feel mentally and physically up to. After I gave birth to my first babygirl, my mom's bf/fiance (they'd been dating foe a little over a year) kept calling himself her grandpa and it just rubbed me the wrong way so I said something and ended up not seeing my mom for a couple months because of it. My mom has missed important milestones in her first grandbabies life because she would choose being his gf/fiance over being a mother to her daughter and a grandma to her grandbaby
I took my baby and he was born on the 14th of November so I think he was less than 2 weeks old 😭 it wasn’t bad though and my baby was perfectly fine and happy.
yes. have them bond & meet the baby while u rest🥰❤️