Am i making the right decision?

I am looking into buying my first car. I dont know anything about cars. My dad took my sister to get her first car and really wants to come with me to get mine. My fiancé on the other hand does not want my dad there. He wants us to make this decision together as he says it will be OUR car... my dad wasnt really a great father figure growing up. He was emotionally and physically abusive and didnt really teach me anything about cars... or really anything at all. He was working out of town a lot and when he WAS home, he was abusive. He never really stepped up. Now that im an adult and moved out he is trying to make an effort at a father daughter relationship. And although i am damaged from my past with him, i cant seem to hold a grudge, after all he is my father. I am open to building a relationship with him. I want to be on good terms and be comfortable around my dad. It honestly takes way more effort to hold a grudge and be mad than it does to forgive. My mom opened up about how my dad wants to come and help me pick out my first car to make sure its a good one. I guess my dad is afraid to ask because he feels as if he would be imposing. I agreed to him coming. My dad is very opinionated and is very knowledgeable about cars and i think its intimidating my fiance. My fiance said no hes not coming. I explained how i want my dads opinion, and i also want the experience of having my dad there, i explained that my dad is trying to have a relationship with me. My fiance said "Why now? He had 24 years to have a relationship with you and you were depressed and suicidal when i came into your life and i feel like ive been trying to pick up the pieces after he shattered you, why does he all of a sudden want to be in your life and help you out?" He also thinks my dad is egotistical ( yes my dad can be sometimes) and my dad does think he's right about everything. My fiance is scared that they will butt heads. Im not willing to hurt my fathers feelings because my fiance is scared to disagree with my dad. I want both of their opinions. I tried to reassure my fiance that his opinion matters more, and that we are the ones ultimately making the decision but i want my dad there as well, it would really hurt him if i didnt include him. Family is really important to me. I think its a battle of ego between both my dad and fiance. My dad knows im getting married and that my fiance and i make decisions as a team. He isnt going to fight with me and my fiance. He just wants to be there. I told my fiance my dad is coming and that is the end of the discussion. Now he is pouting. Am i making the right call?