I don't want my stepdad involved in my wedding.
Why don't you want your stepdad involved?
He doesn't deserve to be there because of the way he's treated me.
He's part of your family now, you should accept him. I would consider inviting him to the wedding.
Nah, I don't want him to come.
Ultimately it's up to you who you want at your wedding, but I bet your step father would be really grateful for an invitation and maybe it would even change his attitude towards you.