This may be long so I apologise in advance if it is! I'll try and be brief.
Current situation is I am considering leaving dp because he is making me and my dd (his step daughter) unhappy. Dd is 6 and is currently under peads for possible ASD. No diagnosis yet but something is definitely amiss. She is a very clever, switched on girl but has several behavioural and sensory issues. Dp cannot deal well with her behaviour and makes her worse and unhappy often. He loses patience and shouts and makes her feel like shit. He has a habit of talking to people in a certain way that is totally demeaning and he can be incredibly rude and unpleasant. He is not aggressive as such but gets angry. I know he makes us both unhappy at times and if it were that simple I would have already left. However we also have a two year old, who he adores and has never been impatient with or angry at, ever. I don't know if it's because she is too young to display the same behaviours as her sister or if it's because she is 'his'.
Also we really need to move house. Our current rented place has a few issues and when things were better between us we wanted to move out of the city to somewhere more rural and to be closer to dd1's dad. However if I were to do this without dp, I'd be in an unfamiliar town alone with two girls and no friends close by other than dd's dad and his family (we all get on well with but try to keep at arms length).
Other option is moving somewhere else near where we already are, which means less upheaval for the girls. I can't afford to stay in this house alone so I'd have to move, with or without dp. The other option is staying with dp and us all moving and seeing if things improve, which I doubt they will tbh so I'm not sure if that's really an option. Dd1 only moved school last October so I would feel bad moving her again, but if we did get out of the city and go more rural she'd be nearer her dad and nature etc, which she loves.
I'm torn as to what to do.
An example of dp's unacceptable behaviour is before our holiday last week. He got unreasonably angry because he had to do the majority of the housework while I revised for my exam. He ended up saying that I think I am always right and everything he does is wrong and he even said "I'm mummy, I'm always right" in a mocking, childish tone in front of my dd. He also got angry and said he was cancelling the holiday in front of dd1 (which btw, he had not paid a penny towards and I paid 200 quid towards, a family friend helped us out with the rest). Dd1 was obviously really upset by this and I hugged her and reassured her. At some point in all of this Dd1 put her arm round my after he had said something horrible to me and he shouted at her not her to put her arm round me because apparently the whole thing was my fault. I eventually got it through to him that I had an exam the next day and if I didn't revise I wouldn't pass. He eventually relented and apologised to Dd1 but not to me.
He was also out of order on holiday when Dd1 got herself stuck on a climbing frame and she wouldn't move, she was quite distressed. Instead of remaining calm and helping her slowly, he got angry and shouted at her and pulled her off the climbing frame and banged her head in the process. I wasn't there but when they returned to the caravan Dd1 was distraught and dp was still banging on about it and stropping around like a giant angry child. I made it clear to him that evening that this behaviour is unacceptable and I will not have my daughter treated in such a way. He knows he is on the brink of losing his family so is obviously now trying to be 'good'. He insists all his issues stem from his own father and he struggles daily not to be like him. I don't understand how, if he hates his own father, would he even behave like him in the first place. It truly baffles me.
Anyway, I've got myself worked up again writing all this so I'll leave it at that. Any advice greatly appreciated.