I get this with my wife as well. She will sometimes mention wanting sex, when sex is not possible (I'm gone for work 2 weeks at a time), but when it's doable, there's no interest. I think she feels safe to throw it out there when it's not possible.

She knows all her excuses are false and made up. So on the very rare occasion when there is a real outside circumstance that would prevent sex, she just instinctively grabs the opportunity and points to that. She's just desperate for the ambiguity that will partially absolve her of her responsibility. She can pretend she wants you but something legitimate from the outside world is stopping her, and you can pretend to believe that the outside factor is the only thing standing in the way.

Here is an analogy - a fat lazy person hates exercise and eating healthy, always has, it's just their personal preference and choice, no other factors. However, the person cannot really be proud of his/her own laziness, and dislikes the way it reflects negatively on his public image if people know that he/she is only fat because of their own laziness. It makes them look bad. What is the "perfect" thing to occur? Let's say a broken leg. It's awesome - now suddenly he/she is soooo super enthusiastic about exercise and moving around, but gosh darn it broken leg is preventing him/her from doing it. He/she gets to look good for appearing to want exercise, and shouldn't be blamed that outside factors (a broken leg) are standing in the way. It's so perfect, in fact, that he/she is just gleeful to make use of the "cover". So gleeful, in fact, that any observant person quickly notices how the enthusiasm for exercise only shows up when a legitimate excuse like a broken leg is there. The idea is to look good for appearing to have enthusiasm. The idea is not to have genuine enthusiasm, but to capitalize on situations that create reasonable doubt. In the situation of no broken leg, the person is quiet as a cricket - doesn't want anyone calling their bluff and exposing the laziness as the reason for no exercise. A broken leg allows the possibility to pretend as if something other than laziness is the source of no exercise.

Same thing with LLs - they only openly communicate desire when its lack is hidden by the presence of an outside obstacle. Getting the benefit of the doubt to keep the game going.

Like a boss who doesn't give a shit about your career plans and advancement, tells you there are no promotion opportunities right now when you meet her for a performance review, but once you hand in your resignation notice suddenly all sorts of promotions show up in your boss' "plans for you". You and her both know it's a fake opportunity that is only there because you're leaving now, helps your bad boss look like a good one.

It's a stupid little game. Call their bluff subtly if you want, or just pretend to fall for it, up to you at this point. My choices would be "Too bad your broken leg is making exercise impossible. Guess eating a whole bucket of KFC alone is your only option now.", "Oh, thanks for the promotion offer but I must decline. It's just too bad that none of your other employees wants to be promoted in my place..." and for the LL - "Thanks for wanting me and sorry that I'm half a continent away. But I want you to know that even if we never see each other again, I'll always remember how we could have been."