[Solved] Dad in Dilemma. I need some advice please!

Thanks for stopping by to hear this huge problem I have put myself in,a positive advice will do me loads of good.
I met a lady 3 years back,she is a mother of two from her previous relationship. Two of the kids had different dads aged 8 and 3 when I met her.
The boy (8) had contact with his dad often and the girl (3) never did,never saw her dad even as he left her mum when she was 6months pregnant (that's what she told me). The girl practically sees me as her dad and I was ok with it tbh. And while I was in the relationship I practically did a lot for the kids. Did school runs even,extra lesson with her son and I was enjoying been a dad even tho the kids weren't biologically mine. The little girl,She grow to love me as her Dad and I grew to love her as my daughter until this huge storm arrived in our relationship.
I am not allowed to go work.
Not allowed to see a friend only if she comes along with me.
Not alone to do anything really and she became abusive (physically).
I still stayed in the relationship because we found out she was pregnant and this time carrying my son.
Try working things out but still didn't work. She became controlling and even tells me the girl isn't my child! Says it to my face.. Also she says words like "I am obsessed with another mans child".
My son was born. Was a day of joy but didn't last long. We ended up spelling up . I was still allowed contact to my son and still played a fatherly role to the girl as well until when she met a new fellow.
I dropped off the kids on a Saturday and the little girl got told off for hitting people with an umberella in the bus . She was crying and her fellow said "its alright I will sort you out' told my ex nicely on the phone about it . I didn't like him booting in while I am sorting stuff out with her. She told me I am feeling threatened and I should remember am not her biological dad. She stopped me seeing her was still having my son . Months later she and her fellow split up and she wants me to have her back . Her daughter was crying on the phone saying she misses me and I couldn't help but have her back .
In between I am in a relationship now and my gf is pregnant about to be give birth in few months . Also the little girl have been coming to mine with my son. Of resent there was a problem . I told her can't pick her from school this Friday as I will be work but will get my son from her during the day . She's turn round and told me 'if am not taking her,I am not having my son'
She is ruining my head,my relationship,and my life
I need some advice sorry for the long essay.