Jeez, you know, these postings on DV bring me back to a place I am sure I should go but haven't as of yet. On that note...
When I was in the midst of being abused, (I am so embarrassed to say this and that kept me stuck too) I remember saying to the women's counselor when she declared that I was (indeed) being abused 'well how do you know I am not the one abusing him?' She looked at me and said 'I can tell from what I am hearing from you, I can tell from what I know of you. Besides, an abuser doesn't come into counseling asking what 'they' can do to help the situation'.
Changed everything for me. Once I acknowledged that I was, in fact, being abused (wasn't easy), I was then able to move forward, deal with my issues on what to do about the stepkids (I was concerned for their safety), and get the hell out. It was almost too late. If you can't leave right now, if something is keeping you there, at least get your head straight enough that you can make a decision that will ensure your future safety.