Have you ever asked your doctor to assess the shape of your pelvis? Some pelvis shapes are more pronto dystocia and benefit from different positions than most other women find helpful. My friend was told that her pelvis would be more prone to dystocia. Her first son was held back on her pubic bone for a but but eventually came out with a LOT of hard pushing from mama. Then baby #2 was bigger and was very stuck. Midwife had her do the all-4s, no change, flipped her back over. Nothing. Eventually she actually climbed onto the bed with her and reached up inside mom with both hands to free baby with the corkscrew technique. Lots of drama and lots of pelvic floor damage to Mom. She has shared the same feeling of disappointment that her body can't just let baby out without the drama. :-(
It's no ones fault, and you've already done the hard heroic work of birthing two babies. And however this baby is born, YOU are a wonderful mom and the birth is a brief moment in time. It's an important moment for sure, but not rhe only moment by which your mothering is measured.