Need honesty - please don't be too harsh

So when my husband and I got married, I knew he had a son from a previous marriage. Which was fine, and I was fine with the visiting arrangements and enjoyed having him every second weekend, holidays etc. I was how ever pregnant with our daughter.

4 Months after having her - my step son came to live with us, after his mother lost everything and was not able to provide financially for him (I was promised it is only a temporary situation).

My husband and his ex are on bad terms, so they fight alot - and my husband would not let her see him for the fear of her running away with THEIR child.

So se resorted to trying to pick him up from daycare without consent. The school phoned me and I work out of town. My husband got a protection order from court.

Now please understan when I say - this is not what I imagined my life to be like. You may call me selfish. But hear me out:

#1 He is staying with us permanently (even if he has a mother who is able to look after him again)

#2 He does not see me as a caregiver (in the therapy session we picked it up - and YES his medical aid is paid by me)

#3 He has NO respect for my what so ever, and never listen when I speak.

#4 I have NO support from his father - he does not recognize that his son is behaving or treating me in this way. And disrespecting me. Eventho it was established by Therapist that he has a behavioral problems.

#5 He is a little shit to our baby girl - and is CONSTANTLY seeking attention, I can't do anything without doing it with him to.

#6 I feel overwhelmed by the negative things his teachers has to say about his behavior, because he KNOWS when ever he does something wrong. He likes getting attention even if it is negative. He will go out of his way to make sure he gets a response.

#7 Forget about positive reinforcement or reward charts he does not care for that at all.

Point of my long post - I don't wanna do it anymore.

My question do I actually owe it to my husband? To stay - even when he KNOWS my struggle, and promises me constantly he will change and help me which never happens, it always ends up with me being wrong for saying somthing to or about the child?