I'm becoming depressed within a blended family dynamic. 
long;short.

We have 2 very toxic and bitter ex spouses who are fully engaged in alienation. I have 2 daughter my teen rejected me and lives with dad. He has 3 children and we have a 1 year old together. We have fought hard to involve all the children within the capacity we can.

there's so many blows but his ex wife and my ex husband have befriended each other and use information between each other to add another layer. This woman is a racist dealt with by police and my children and I are POC. I try to focus of some normality for my youngest daughter whom I'm primary carer and our baby son. 
 

it seems dad can not let go of guilt and any tiny slight or benefit he perceives my children to receive will trigger him. He lost his relationship with his dad to apprently his evil wife so I feel he is trying to correct that as an adult but over forces it and doesn't compromise.

eg. He had to go to court last year for contact and to be allowed to take the children on homiday all 8 of us together abroad. This year I've booked a holiday as we can't afford them all just my young daughter and his young daughter. But her not her won't give her passport details or allow her to go again. So I think I'm taking my daughter regardless and should be able to take my baby son. But he gets defensive and says his other son should be going... but his ex doesn't allow him. So I'm left unsatisfied and leaves my youngest without if I don't go ahead anyway.

next his teenager, who blocked me the day I gave birth to my son and then came round to again start acting out on hokiday abroad and called me a "fat scruff" told me she's not coming my home if I'm there. I say suits me I have boundaries to which he says "no she's a kid and I have an order". She comes and i vow to disengage. She says 4 months later I hold a grudge. I explain I hold no grudge at all I understand she is learning through life but I have boundaries and she's not to disrespect me any longer.  She is of an age she comes the house and doesn't speak the whole weekend or demands what she wants etc. she's started to dance next to her home on Saturday mornings. So hr gets home from work 7pm Friday eveni by to all of our children then gets up and takes them all back to where they came from for 10am. I suggest maybe it's easier for her to stay home and maybe be collected Saturday after dance as it has an impact on us all as now the day shifts to revolve around it. He jumps to defence and says no whatever it's his time with her, but he's not with her... then he complains he's exhausted and he is constantly late and missing work because he tries to fit it all in. We live 10 miles from their home. 
 

There's too much I guess to write down but I think overall I feel his need to keep my bio child specifically level with his means I can't have a normal life with my children and include his, it's like he wants me to act like their bio mum but with a home not big enough and a we can't even fit into one car. I have to leave my baby son behind all the time. 
 

sorry just ranting I guess but looking for similar experiences to know what to do. 
 

we were on holiday last weekend and argued a lot. Im recovering from surgery so it's been a struggle. I tried to discuss not wanting to leave my baby son out all the time I am his mum. We were talking about the summer hokiday with his youngest daughter and mine. I said ideally I'd take my baby as I don't want to leave him im his mum. He said but we're leaving my other son and I said with his mum and sister yes. Im also leaving my eldest daughter. He said im leaving, that's disgusting and im out of the relationship. He's calmed down and just IGNORES the issue and likes to avoid. I don't think his explanations work for our situation. We're leaving my son behind because he doesn't want his previous children left out, but I accept my eldest daughter misses a lot due to the situation we're in and she doesn't display the same jealousy his children are exhibiting, I feel he makes issues out of battles that should be positive. Ie we're including his daughter or trying to even though their mum fights it regardless.