I love my mother very much but I didn't want her, or my sisters, in the delivery room with me. I couldn't think of a more private, vulnerable moment I could have in my life and family dynamics would have just added to the stress.
My husband and I make a great team and he was awesome during delivery. One of my sisters isn't so lucky. Her husband is a great guy but not the best support person in a stressful or emotionally trying situation. She got a doula for her second child and was very happy she did. The doula is a 3rd party, someone to help that isn't a family member or close friend. Someone neutral to assist in whatever way is needed.