Ladies what do I DO .

I'm 21 years old and I'm having my baby shower this Saturday. Unfortunately my parents have been divorced for about 4 years now , and my mom is now engaged to another man. My little sister is convinced I should invite my dad to my shower which will be held at my MOMS HOUSE. I just don't want anyone feeling uncomfortable especially my moms finance. As his oldest daughter, I want him actively involved in his grand child's life but do not want anything to happen to my dad the day of my shower. I don't even know what terms they ended up in and even if my dad it to step on my mom's property. My sister already told me she will not be attending if my dad is not coming, and she will be returning my gift... 😩😩🤦🏽‍♀️🤦🏽‍♀️🤦🏽‍♀️ #HELP