Take your home back. Be cordial to them but do not bend over backwards to accommodate them. Do what YOU want in your own home, don't hide in your room.

There is no reason to feel bad about not doing for them. Your husband is their father, he is the one who should be guiding them and doing things for them.

Why do feel that they hate you? You said in your bio that the straw that broke the camel's back was them not wishing you a happy birthday. I don't know what else they have done to make you feel disrespected but the birthday thing is not a big deal, in my book. I know that it is, to a lot of step parents, but really, your step kids have no reason to care about your birthday.

And no, my husband does not tell me that anything is all in my head. He knows that his daughter has mixed feelings about me. On one hand, she wishes that I were her mother, on the other hand, she resents the hell out of me.

I doubt your husband really believes it is all in your head, he just doesn't want to deal with it. Even if they don't like you or care about you, they need to be respectful.

Oh no, no, no...not in your head nice lady; not at all.  I would think you would rather have positive thoughts--if at all possible. You are dealing with a weakling daddeee (like many of us), who makes excuses rather than address the child/adult that views him more like a paying playmate than a father. Never let this stupidity oozing out of his mouth get into your head. He is a dysfunctional parent, who would rather cast blame than take responsbility.  Try to stay away from their sickness as much as humanly possible; maybe he will wake up one day; but never count on it. Just look out for YOUR own happiness, and stop worrying about his....

My DH used to say the equivalent statement "what did my kids ever do to you?"

He was being a coward because he did not want to deal with what they were doing to me. Until I was ready to leave.  

He later admitted he saw what they were doing but chose to stick his head under the rug and hope the problem went away on it's own. Because he learned when he was younger that a lot of time if he did nothing, his problems would go away on their own.  

These precious kids of his are now in their FORTIES. He considered them his peers, went bar hopping with them, treated them like his buddies. He did not want to lose his buddies, nor did he want for BM to become the Favored Parent, which by the way, she did when he finally made his marriage his priority. 

When I was ready to leave, he was finally ready to stop being a coward.  Unfortunately that's the moment of truth for many of us...some of us continue with the marriage  (although with a big chuck of respect for DH missing), other marriages end at this point.