Try rewording this "I confess I have decided to just keep trying to improve myself, and stay in the lifeless marriage." to I confess I have decided to just keep trying to improve myself, and figure out what it takes to put life back in this marriage.
The more you describe the more you sound like me. I have been in the public eye alot and with that comes the groupies, fans and so called friends. These people really stroked my EGO and I had a period in my life when I lived for all that and could not understand why the love of my life could give a rats ass about the public things I do....
May I suggest, putting a toy or 2 away now and then, sit on the couch and shop with her...... no mater how much you may hate it.. I know where you are coming from with this... I used to hate shopping so much, I would go but I had an attitude the entire time and would huff and puff if she went around the same rack twice. This can be slowly fixed with a different outlook. For women shopping is an activity, for men it is a chore. If you go with her and actually participate in her shopping thoughts and activity, you may learn alot about her.... she will like it because you are showing an interest in her thoughts, likes and dislikes.. While shopping her eyes, face and the things she touches are tells of things she will not put into words and you can key in on them. Now I warn you.. you will never like shopping as much as a woman, so limit this activity and behavior, because to much can also get ugly.
I have been married 30 years and we still find out more about each other each time we shop at the grocery store.... Some times the trip ends in good old silliness like her actually taking my suggestion of riding on the end of the shopping cart as I push the goods across the parking lot to the car. fine behavior for a couple of 49 year olds.... but i hope you see what i mean.
Here is an idea. On one of the good, no self pity days....The next time she even hints it is cold out, make sure the kids have a place to be and take her to the Mall (yuck) and tell her it would make you happy if you could get her some warm, cozy and girly gloves hat and scarf, or perhaps fuzzy socks..but you want her to pick them out. No mater what.. reserve the smart ass comments and utility suggestions and stay connected with her methods of shopping, you can learn something. LAugh when it is funny, wink when it is nice and make a quick ugly face when you dont like it... but if she likes it anyway... you accept it happily. If all is still well push the limits by taking her to eat icecream or something... even a round of skillball at Chuckie Cheese to see who can get the most tickets.. Add fun and silliness to things just between you. not everyday and not on a calendar... just when you are inspired by your heart or when she needs it...
anyway.. you want her to be interested in you... you need to do the same.. even if it does not seem natural and her likes are limited.