One of the sharper arrows (to me) in the quiver of those LDS individuals seeking to show me and those like me the error of our ways is the simple invocation on "covenants" we have made. A "covenant" in the Mormon sense is a contract an individual take out with god directly. LDS leaders like bishops make judgments on a member's fidelity to their covenants only under the influence of the Holy Ghost; it is always understood that this is an agreement with deity. Covenants are made at baptism and confirmation to begin with, and the ultimate covenant are made in the temple.
The general theme of covenants involves adherence to the LDS faith and obedience to its commandments (Word of Wisdom, Chastity, Tithing, etc). It is understood that specific blessings usually accompany the fulfillment of each (health, happy family life, material/economic stability respective to the aforementioned), and these are god's end of the deal (along with eternal salvation, of course, it's never supposed to be a particularly lucrative deal for heaven; it is all for the benefit of the members). One important caveat is only god may set the terms, it is then up to the individual to make, adhere to, or break covenants as they are offered. While it is still considered sinning if a non-LDS person breaks the commandments outlined in the faith, it is considered far more grave for an LDS person who has made covenants to engage in the same activities; not only have they sinned against eternal law, but they have done so knowingly and "lied to god" by breaking their word to him.
Things become interesting when someone loses faith, however. To their LDS friends, family, and leaders, they are breaking covenants by distancing themselves from the faith to which they have made commitments; it is no different from any other sin. However, the individual may no longer believe in god, or at least not in the very specific description of god outlined in the LDS faith (along with the covenants he offers). Here is the potential Catch-22 that has been presented to me: I have made promises, and if I am a man of my word I will keep them regardless of doubts I have. After all, the most basic form of decency and morality is integrity!
This has bothered me a bit. My integrity is incredibly important to me, though I'm by no means infallible in that regard. My thirst for greater integrity actually contributed to the process of my loss of faith; it was painful and I did not want it to happen, but I could not lie to myself. Is willingly abandoning the covenants of my believing years a betrayal of myself? In the LDS view, god sets the terms of the covenant and only he can change or terminate it, but I no longer believe there is a god, so there is no one to release me. I'm presented with a Catch-22, and I believe there are some LDS individuals who would consider this final; I cannot leave with my integrity intact.
The more I ruminate on this, though, the less straightforward it seems. The covenant was only with god, a being who (in my view) has turned out to be fictional. I was deceived or mistaken, shanghaied by an idea which turned out to be so much wishful-thinking. In serious court of law, I doubt that the contact would be considered binding. Furthermore, even if we consider the contract's existence outside the context of god's existence (in the strict LDS sense), god cannot possibly uphold his end of the deal if he does not exist (I have even considered that there might be an unstated stipulation in the contract that he exist, perhaps this is an unwritten feature in all contracts). Finally, I would propose that if there are two participants in the covenant (myself and god), and one turns out not to exist, the covenant becomes a farce if all power to modify the covenant exists in the hands of the fictional entity. I'm now the only participant in this increasingly-dubious agreement. The only reasonable thing to do it declare the contract null and void, and as the only participant, enforcer, or potential benefactor, I have every right to do so.
Some LDS individuals might remain unconvinced by my reasoning, but I would point out that the LDS way of thinking operates under the same conclusions when dealing with conversions to their own faith. Members of other religions who have doubtless made commitments of some sort are not counseled to honor those once they come to believe they were born out of adherence to mistaken beliefs; the LDS church instead encourages converts to throw off whatever promises they've made to a "false" system of beliefs and join in more "real" covenants with a more true concept of god. I think this is a reasonable attitude by the same logic I've already outlined, provided these people now believe the tenets of the LDS church.
I may still be considered a covenant-breaker in the Mormon view, but I don't believe any reasonable LDS person can think they can appeal to my own sense of integrity and expect me to reach the same conclusion.