It might be worth looking at what happened in your previous labours, and if things happened that may have increased the risk of having a retained placenta.
did you have syntocinon during your labour? did you have a medically managed 3rd stage? Was your cord pulled on before your body was ready?
did you have skin to skin time with baby? did you feel safe and secure? how long did they wait for the placenta to come away?
Talking to a private midwife may offer a different perspective on why things happened, and what could be done differently next time.