Academic Journal 6 - 'Ourselves Alone'

I’m thrown by act 2, scene 1, where Donna has a monologue about the devil. I don’t quite know what to make of it. It seems like she is drawing a connection between this devil and her asthma, and says that Liam’s imprisonment made the asthma and devil vanish temporarily. So it seems like Liam and the Devil are tied together, but it seems like such an obviously stated connection that I have trouble accepting it. Liam’s behavior towards her in the rest of the scene certainly indicates he is a relentless and negative influence in her life, but why include this devil business?
Since the devil first appeared while she was with her first husband, and vanished when her second was put away, maybe she has trouble really accepting that she can live without a man in her life. Blaming the devil for things we don’t like is not a new trick, and personifying him into an oppressive presence could be a way of blaming the asthma on an unavoidable evil rather than a husband she could leave. The attacks start while unhappily married, and continue until the man in her life is forcibly separated from her, at which point they clear up. When he is released from prison and returns home to her, the attacks resume. She’s clearly deeply devoted to him, as she tells him in the same scene, and so it would presumably be difficult for her to accept that he is the trigger for her attacks.
I’ve tried to come up with some grander connection for the devil, but I’m hard pressed to do so. He seems to be a Donna-specific tool for the author to externalize the character’s conflict over her marriage. Maybe the last bit of the monologue, where Donna tells us that she asked the Devil to leave her alone and he agrees to do so (though not, she suspects, for long) is a way of hinting at growing strength for the character, that her time away from the husband and devil have shown her a better life that she is almost willing to fight for. This isn’t particularly supported by the end of the play where Donna suggests she has lost the ability to be happy, so maybe the fact that she suspects the devil won’t stay away forever is the key, showing that she believes herself trapped no matter what, with only Liam’s periods of absence to look forward to.