Ex at baby shower?!

My boyfriend invited his ex to our baby shower, I know they are good friends but this is to far. A lot of his family that I haven't even met we be there and they all have met her. I feel like this is going to make me feel awkward and uncomfortable at my own baby shower. He said he cant uninvite her now, I've never even met her before I don't want her there. What do you think am I making it more serious then it is? What would you do?