My best friend had a baby 2 months ago, her DP has a 10 year old DC from previous relationship. Last night Mil was babysitting and DSC was getting dropped off there. The ex brought the child in so mil put baby in another room and hid all the baby stuff so ex wouldn’t know she had the baby. She even joked that it was a close one as she nearly left his blanket out. My friend was upset about this but her DP said she’s being too sensitive. She’s just come to mine in absolute bits about it and I said there’s no way I would put up with that. Is this normal behaviour?