should I invite my husband ex wife to my baby 1st bday

Hi ladies. I need you opinion in something. Should I invite my husband ex wife and her man. I have been with my husband for 6 years already and him and her been split up about 7 years. She had someone already before he met me and she had a kid from the other guy before me and him were even married.  Since I gave birth I have gained some weight of course and my baby bday is coming up in two months. I don't know if I should invite her to the birthday or his other birthday, cuz she have had invited me to her new baby bday a year ago. I need you opinion. I kind of want to look good after the baby just to piss her off or I should just invite her and not care, just cuz she invited us to her new baby bday last year. Ps. She doesn't really like me as it is and I know she will say some stupid shit about me being some what bigger after the baby.