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This is what I'd do if I were the LW. Keep taking the meds as long as he doesn't mind the side effects. This way he doesn't fall back into the old patterns. Go into marriage counseling, alone if his wife refuses. Once he has a better understanding of the relationship and what he really wants & can reasonably expect, then & only then should he decide what to do. One thing he needs to understand is why he stuck with the marriage to this point at all. I think that lack of sex on the honeymoon was a big indicator of things to come. Of course hindsight is 20/20.
My only concern in this is the kid(s). Protect the kids as much as possible.