"Letting her know how you feel" is easier said than done. I have not heard from a single person here who was the "low-desire spouse" and really understood what the "high desire spouse" was going through. If you read through the stories of the "LD spouses" who put their marriages back together here, they consistently talk about a time when they finally really came to understand how much the HD spouse was suffering. Until that epiphany came, they were convinced that their HD spouses were making a big deal out of nothing. They thought their HD spouses just wanted a quick physical release, or they thought they just wanted to brag to their friends about what studs they were.
For my wife it was several discussions into The Sex-Starved Marriage when she finally started to get it. She broke down in tears that were somehow different than all the floods of tears before. At that point, it isn't just the realization that you've been suffering and tormented for years, it's also the realization that they've made it worse by dismissing your feelings and denying that your suffering is real or important.
My only advice is to get other sources involved. The LD spouse has a hard time taking what the HD spouse says about sex at face value. They can't seem to help but wonder if all the talk about hurting and suffering is just a crass ploy to get laid. Cinco mentioned his sex therapist, who probably wasn't saying anything he hadn't said a thousand times, but because the ST wasn't trying to get sex from her, Mrs. Cinco had to give her advice a fairer hearing. For me it was the book, and later a friend of my wife who was the HD spouse in her marriage and could tell my wife how lousy it was.
The "Flannel Shield" is another matter and will take a lot more work. It's a matter of her comfort level, and that's going to be one of the last things that gets any better. Even if this all works well, you should still expect a period of awkward, fumbling attempts at intimacy that don't go well. Just laugh when that happens and keep going. There will probably be times, too, when you should pass on sex, but whether out of desperation or determination, will try to forge ahead. Just laugh it off and keep going.
My wife had the same flannel shield. Her "signal" for intimacy was to go to bed before I did in a silky teddy, and over the years those teddies began to gather dust. When we started working on this, she tried to bring the teddies out of retirement and it worked well, but it also worked as a limit for her. If she didn't have one on, it was likely impossible to get anything started that night, because it had been "marked" in her mind as a non-sex night. Now it doesn't matter much what she wears, because I honestly don't care. The slinky stuff is nice, but it all comes off! Don't get too hung up on the outward symbols of sexiness. She's the sexy part. The rest is just decorative.
She makes a real effort now to stay in bed and snuggle after sex. But that took a long time. Even then, she'll snuggle for awhile, but she almost never falls asleep that way. The truth is, she can't. She genuinely gets cold and uncomfortable, and she needs her warm PJs to sleep comfortably. And now that she snuggles with me for at least a few minutes after sex, I find that I just don't mind much when she gets up and puts on the PJs. She always comes back, after all.
You may not end up doing things exactly this way, but my point is that we found an accommodation that lets us meet halfway. Would I like to sleep naked with her all night and wake up in her naked arms? Sure, but it isn't a big deal and (this is important) she has shown me that it's not some kind of personal rejection or a rejection of sex when she puts on something warm to sleep.
Besides, the truth is I could probably get her to sleep naked by turning up the heat in the room to a temperature that would leave me sweating and awake. I'm just not willing to do it!
