Would you be friends with your stepchildren's mother?

Mr

I tried very hard in the beginning to befriend my husband's ex wife. But she was always a HUGE jerk to me. Then when I became pregnant with my first she became out of control. She showed up to my apartment and punched my stomach. I was 10 weeks and I lost the baby. Not sure what caused the miscarriage but in the end she got what she wanted, she didn't want me to have my husband's baby. We cut her out, I became pregnant again and she is now begging for forgiveness. She wants us to get along for the kids but after the lost of my first baby and how she laughed about it I do not like her at all. period. She wants my husband and their kids and her to spend the holidays together. I do not want me or my daughter around her, therefore our families would be split holidays. My husband is upset that I don't want to get along with her, but I cannot forgive her.