First off, we have to deal with the fact that Lynn regards John's staff as a harem of beautiful women who do what all beautiful women do to 'plain' people such as herself: destroy any chance she might have of happiness because as we all know, beautiful women not only ask to be ogled by perverts, they long to hear the anguished, despairing wailing of the women whose lives they were built to ruin.
After ticking off the box marked "Rod's girls want to wreck my marriage because that's the only reason women enter the medical profession", she ticked off the box marked "Rod/John only pretends to respect my/Elly's opinion" when she wrote the "We hire the woman who doesn't make Elly feel threatened" strip.
Finally, we have to contend with the fact that John is presented as being a piss-poor dentist in the first place. This seems almost engineered to destroy Rod's reputation so that he might be a 'good' husband, stop flying around and trying to cheat on her with his harem and do something useful with his life by devoting himself to insulating her from a world that frightens her. You see, I don't think that Lynn ever got into the habit of looking after herself and still seems to need someone to take care of her. If Rod has to give up something he loves to make that happen, Lynn seems to view that as being a very fair trade indeed.