I thought the conditions of the "What if" presumed Barnabas opening up to his love of her (Angelique), in which case the situation becomes more complex. Obedient? Well--methinks she'd've tried. Mind you, this whole scenario presumes a degree of self-awareness that neither character would possess for a long, long time.
Read an interesting something-or-other recently about a Hindu belief that at Hate and Fear and Love are emotional siblings, but that each crowds the others out. There is a point where one feels for another all three, but only one at a time. Thus when Angelique hated Barnabas, she couldn't actually love or fear him at that moment. Likewise when she feared him, or loved him. Ditto Barnabas--that when he feared her (for example, feared her unraveling his life by insisting upon a relationship) he could not love her. Likewise, he could not fear her while loving her, nor while hating her at that moment. It is a tricky idea to get a handle on, especially when you consider this came out of one of the oldest civilizations on Earth. Helps me to think of it as reading a book, listening to music and watching a movie at the same time. You can do it. I can, certainly. But only one has your full attention at any given moment--and actually, it is about more than one moment. Consider trying to read one word, then listen to one note, followed by one second of the t.v. Apart from the fact it would make everything incoherent, we simply couldn't do it. Rather, we would stray between the three as the ebb and flow of our experience took us, including what catches our attention.
Methinks that is kinda/sorta what the relationship between Barnabas and Angelique was like. They loved each other--oftimes in a dark, vindictive, guilt-ridden and jealous way. But that love was often eclipsed by the fears each inspired in the other. Angelique was terrified of losing Barnabas, of his finding out what she'd done, later of his killing her. Likewise she hated his cowardice in the face of their love, hated his devotion to Josette, his duplicity, his refusal to even try and forgive. And at any one time, her love or hatred or fear dominated her heart.
Likewise it worked with Barnabas. His relationship with her began and ended with love. But he also feared her, partially methinks because she made him behave in ways of which he did not approve (oh, those New England Puritans), as well as the fact that she was such a strong personality in her own right (oh, those 18th century men). And of course he hated her for all she'd done. But it was interesting how at any given moment he only seemed dominated by one of those emotions. When he feared her, he tiptoed around her and was extremely careful. When propelled by hatred, he went on total attack, often to a reckless degree. Yet at the end he waxed poetic, saying she was the only woman he ever loved.
Perhaps the real trick would be to figure out how Angelique and Barnabas might have found a way to love each other at the same time, for more than a few nights in the Carribbean?