Adinva, I think of it as the question I'd like to ask such a woman in order to flush out a more truthful answer. And I agree the answer is probably going to be like the reasons you list.
As for point 2, there are no guarantees in any situation. Any statement is conditional on the present. Even a marriage that is good is not guaranteed to continue that way. Most marriage end in divorce or sustain unfaithfulness, or both. In matters of sex and love, if you need a guarantee, you'll never have either one of them regardless of the situation, be it marriage, FWB, or whatever.
But,yes, generally I agree with you. Which still means that what it boils down to, even if the LD woman doesn't really intend the particular meaning, is that what's important for her is that her husband stay celibate indefinitely. Not that she really wants it that way, but just that any alternative is more unpleasant for her.
In fact, I've even heard of women who refuse to have sex with their husbands, yet also insist that he not masturbate. So, yes, some LD women are living in total fantasy land.
As for this forum giving me permission, LOL. That's a good one. Guilt, moral approval, etc., are the least of my issues.
