Insecure men are clingy men that seek approval and don't take alot of initiative in their lives and I know that isn't attractive.
I think the point robx is that you can't make an insecure man secure by telling them initiating sex will make them appear more secure.
They have to get to a place where they feel secure and that requires detachment and at this point I agree that dating might help too. You just can't fake it and that is basically what you are proposing because it just isn't real.
I agree you can't make anyone more secure by telling him to be more secure but you can get some measure of success by breaking free of the insecure mentality by actually doing something different from what you've currently been doing.
If sleeping next to his wife for several months in the same bed and not initiating sex has kept him "sex free", possibly taking initiative and speaking to his wife about it might get him somewhere different.
Doing the same thing over & over again but expecting different results is the definition of insanity.
I'm just saying do things differently if you want different results.