If you want fertile eggs, you must let them live together. That part is simple, No?
The fact that they exsist in nature means they part up. The fact that many people, including me, breed them in captivity, means they pair up here too. The real question is, why do you have them apart.
I would imagine, you have them apart because of fear. Your afraid to put them together. Does this have anything to do with your individual monitors? I hope your not to cheap to give them a cage large enough for both. Are there any other reasons?
If your afraid something will happen to them, then get rid of the female and keep a male. Because, something adverse is happening to the female now(check out Roberts post) You can take her to a vet and have her fixed.
Breeding monitors is dangerous, not because of the monitors, but because of our poor husbandry.
If your intentions are to allow them to breed, then you must allow them to be together. Use common sense, no one here can tell you what your monitors will do. You have to watch them and judge for yourself. If one trys to kill the other, then seperate. If they have little tuffs about this and that, you have to live with that. Its rare for an adult monitor to not have scars.
With argus, you will indeed need to work the monitors, that is, feed the male in a seperate cage(they are pigs) Or move the male out when the female is nesting or recovering from the stress of nesting. Or you may not, thats why you are the keeper, its your decision. One huge reason you may have to seperate them is they may try to eat eachother. In truth, thats only if they are starved to death and have no other options. In my opinion, the difinition of, same species cannibelism is, they are starving.
I would think you should get rid of the female. The reason I say that is, you should have had them together by now. Monitors, like all other captive animals, I know of(including us), learn to get along with others, its not instinct. The longer you wait, the harder it is to learn. Most likely you will not have a problem, but only you will know. F