It may be that the therapist thinks that you're a bit too obsessive over the whole thing. By attending a "few" meetings and trying to be social with JWs it might help you to avoid being so critical of them all the time.
They may be thinking in normal relationship terms...by your taking an interest in your wife's interests, to a point, it can build a stronger relationship. One doesn't have to abandon their self found belief system away from the former group think, but to be a little open minded to your wife's position and beliefs might help you to be less critical, more accepting of her and her position thus strengthening (over time) your relationship with her.
If you're not willing to do that, then divorce may be your only way out of having JWism part of your everyday life.
I'm not saying that I would agree with such a suggestion, but I can see someone saying that. Even physciatrists and threapists who may understand the dynamics of cults/control groups better than the common layman still do not know what it's like to have actually lived in one and escaped.
I do think that as long as family members don't continually throw JWism in my face and try to guilt me or force me back to meetings, then I'll leave them alone to believe in it as they wish. I don't look for every oppurtunity to show them up or prove them wrong. I know what I know and I know that they're wrong, but I can't change them if they don't wanna change so I just work on myself and leave them to their own devices.