I’m not sure who spreads information like that, but my suspicion is that it’s either women who have had very little actual experience with actual guys, or else a secret cadre of men purposely disseminating misinformation that will make life easier for dudes everywhere who want to dump their miss.
There’s no “proper code of conduct” regarding breakups, and if there were it would have long ago been hurled at someone’s head and destroyed in a fit of passionate fury. Give some thought to why you would want to “get him back” if he’s the kind of guy who holds the possibility of a breakup over you, or simply isn’t into you.
If you still do want him back, then I think your best bet is a pre-emptive strike. Bring this up; talk about your feelings about the relationship, your suspicions, your concerns and your desire to work on building the relationship up again, before he has a chance to pull the trigger. Sorry for all the war metaphors.
This is a case where open communication can only help, and it’s better to act than react. If you just wait passively for him to dump you, I sincerely doubt anything good will come of it. I mean think about it: if you’re this gung-ho to win him back after he “inevitably dumps you,” why not start the effort now and save you both the hassle of moving all your crap twice?
And if it does come to a dumping, do yourself a favor: don’t Stepford Wife it. Kick, scream, cry, express yourself in words of four letters or fewer. We’re human beings, dammit. If you can’t make a scene when dumped, when can you? The way I see it, everyone’s got to have at least one horrible, traumatic breakup experience. Viva life! Viva Mexico!