Rush Sex, yeah, that is an instant board classic, Mojo!

I too would nauseate intensely if I had to have sex with him tonight. However, I never would have married him--or been at all attracted to him--in the first place.

I don't understand how a person can feel disgusted by someone that they once found attractive. Disillusioned, yes. Resentful towards, yes. But nauseated? This seems so harsh . That is really putting a whole different spin on things and has, imo, gone past any kind of normal LD feeling of just not being in the mood or feeling overwhelmed by another's demands on you.

Or maybe I just don't understand being LD at all and this is quite normal and to be expected!

I don't believe that my H was ever nauseated by me. But I do believe that he was disillusioned by the person I had become, inside and outside. I did not lose all of the baby weight after D5 and this impacted his desire for me and compounded whatever religious hangups he was having. After all, it is MUCH easier to deny yourself the pleasure of sex..all in the name of being more devout...when your spouse isn't doing all that much for you in the first place.
I don't think it ever got close to the nausea stage; I think he simply was less turned on by my postpartum body.

Now the converse was only sortof true. On one hand, he WAS more attracted to me after D2's birth when I lost all of the weight and returned to my normal shape of 5' 9" and 132 lbs.
On the other, it wasn't a failsafe guarantee that he would want me. Sometimes it affected him and other times it didn't. Sometimes a certain pair of jeans (oh how I long to wear those babies about now!:) would drive him crazy, other times he could care less and not even notice.

However, I live with the same fear that you have: namely that if it can happen once, it can happen again. I used to harangue my poor husband for reassurance constantly that this was not going to happen again. He got fed up with that but I was a bottomless pit of neediness. How desirable, right!
But having your H tell you that he wasn't sure "where a wife fit into things anymore" (meaning should he have been a priest) was terrifying. I had a 2 yo and a newborn when he made this announcement. I did not fear him leaving me for financial reasons; rather, I was just PISSED that he would even be considering this in the first place. For sooo many reasons--I am a stellar wife, if I do say so myself; he should have never married if he felt such a strong pull to the religious life; I was damned attractive and felt trapped with a man who would rather go to church than ML to me...gosh the list was endless on why I was mad at him. It took me a long time to let go of this.
My point is that I was really in shock that any man could have not been thrilled to have me as a wife. The thought was devastating that my H was able to resist me with ease and needed me much less than I him.

BUT, that was then, this is now. He no longer feels that way and cannot believe that he was once capable of such a massive disconnect.

For my part, I do believe that the chances of this happening again are verrrrry slim. But the fear lingers and never totally goes away. That is why it is so hard for me to join him in spiritual discussions--because it is a trigger for me...I think that by filling his love tank this way that I am somehow encouraging him to nurture this side of himself and that it will feel so good and natural to him that I will lose him forever.

He really did a number on me but I have forgiven and (mostly) forgotten. All I can do now is to trust that he will not make the choice again to disconnect from me and this marriage.

I DO trust him but I have to say that the wide-eyed girl who married him is gone. I used to believe that nothing could affect his love and devotion to me and now I know better. So those initial feelings are gone, but they have been replaced by feelings of someone who has been emotionally abandoned and worked their way back and now CHOOSES to be married to him.

Ok, enough rumination.
Let's get back to the nausea.
I thought about it today and realized that there are definitely cases where I could become nauseated by the sight of him...such as if he became obese, or stopped brushing his teeth and they rotted, or stopped bathing and smelled like a sewer, or he became addicted to drugs or alcohol and was never sober, or he began abusing me, etc.
In these cases yes I would be nauseated by him.

But back to my SIL...that isn't her problem. Her H takes excellent care of himself and is a handsome guy.
So there is more to that story I guess.