Yesterday I was trying to understand the problem. You sounded frustrated, annoyed, and upset that you haven't had sex with your husband since Feb. and I was thinking wow you'd think he'd be the one complaining about that. But in fact he is or has and because of a whole list of reason some having to do with sexual technique (not picking up non-verbal cues...or your direct verbal instruction) and honesty issues coupled with partner priorities (living, finances, etc) then add needy and clingy and it is or has become a major turn off.
Did things get worse after Mr. A moved in?
So from where you started have the primary and secondary roles been switched? Not in a formal sense but in a functional everyday application sense. Has that become an issue for your husband?
From day one you start this non-monogamous relationship. About a year in you change medication which wakes up your lost libido. Shortly after that you find Mr. A and 6 month or so you get married (last Nov) honeymoon last feb. The honeymoon sex was the last sex ? What a powerful statement that is in retrospect. I have to ask How was it or how would he rate it? Does he hear you high libido types going at it night n day, day and night. That's got to sting every time the door closes.
6 months of therapy and no ones seeing any progress, is the therapist poly friendly and how often do you meet?