I have a six week old (mine and DH) and my 7 year old who I share custody of with my ExH. I am on maternity leave from the NHS but am still doing a professional MSc (funded) whilst on leave. My husband works long hours in a job he got recently following the collapse of his business. Due to this I do all Baby related care and night waking (breastfeeding). I have a Uni deadline on Monday and have been quite stressed about it. On Monday he informed me my stepdaughter would be coming over on Wednesday and that I would need to look after her as he and his ex were working (she is 12) I had not been consulted about this and assumed that it was obvious I was not able to take on another child over half term due to sleep deprivation, deadline etc. My DSD is lovely but very high needs and has behaved badly since the new baby arrived . I have explained that my mental health is more important than her feeling bored at her Mum's house and that if he wants to have her extra over holidays then he should book holiday. His normal arrangement is EoW. He shouted at me and called me a selfish b*tch. AIBU to say I can't manage her care as well as my other children?