Lee - yeah, you've come to the right place to find out about thyroid disease!!! I've been too high, had my thyroid irradiated, went REALLY low, and am now thank goodness doing well. Also, I'm an M.D., so I know all the technical answers.
Libido - yes, definitely affected by thyroid disease. When you are low thyroid, every day can be like wading through knee-deep mud. Everything is such an effort. Even sex. This can definitely get better as they replace her thyroid hormone. But be patient - it can take a while for them to get it adjusted properly. They usually start off with a low dose, wait six weeks for the blood tests to even out, recheck, then increase the dose if needed, wait 6 more weeks, etc. For me, it took 4 months from the time they started me on synthroid to when I finally started to feel like a normal human again (unfortunately - just long enough for my H to drift into an affair )
Low thyroid can also cause depression, thinning hair, muscle weakness, muscle cramps, dry skin - all kinds of bad things. With any luck, your W will eventually start feeling better than she has in a long time.
Be supportive. I still can't entirely forgive my H for not being there for me during that time, although I now realize his own depression was playing a part in that.
Also - be aware, as they replace her thyroid hormones - don't rely entirely on the lab numbers. It's still a "normal range" - meaning you could be at the low end of the normal range, but it could be too low for you - you may need to be at the high end of the normal range.
Feel free to ask me any questions. Oh, and Mal had her gallbladder out recently, didn't she? She might have some pointers for you (she's over on Hopefulness).